Diamonds Price and Certification - Does price vary?

Prices of Diamonds Graded by 3 Different Laboratories

Diamond Grading Laboratory Survey
 
by David Atlas[1], Garry Holloway[2], and Leonid Tcharnyi[3]
August 6, 2004
 
Abstract
 
An analysis of trading prices showed that the trade adjusts prices based on expected strictness of diamond grading reports.
 
To confirm or deny the trades expectation of grading strictness, the authors conducted a small 17 diamond independent survey of GIA, AGS and EGL USA lab grading. The diamonds were anonymously submitted from three different sources.
 
In half the cases AGS clarity grading was one grade stricter than GIA. In two thirds of cases EGL USA color grading was one grade softer but clarity grading in a third of cases was stricter than GIA. Industry opinions were confirmed and by large each lab graded consistently to its own apparent standard, considering the high degree of human subjectivity involved.
 
In conclusion: The study confirmed that business to business Internet listings effectively priced diamonds graded by these laboratories  
This independent survey of GIA, AGS and EGL USA lab strictness and consistency was conducted by anonymously submitting 17 diamonds from three different sources. In half the cases AGS clarity grading was one grade stricter than GIA. In two thirds of cases EGL USA color grading was one grade softer but clarity grading in a third of cases was stricter than GIA. Some myths concerning these labs were not confirmed; variations in grading indicated a high degree of human subjectivity.
 
An analysis of trading prices for the diamonds showed that the trade adjusts prices based on expected strictness of the grading reports.
 
In conclusion: There are brand and price differences between not just diamonds, but also laboratories. An informed buyer can choose a diamond with a more prestigious report and easier resale, for possibly a higher price, or a diamond with a likely lower cost. ----->
 
1. Introduction
 
Diamond prices are dramatically dependant on the 4C's (carat, color, clarity and cut); a difference of only one color or one clarity grade can result in price variations of 3% to more than 25%.
 
For many years, buyers and sellers determined diamond grades by themselves. But in the 1953 the Gemological Institute of America (GIA[4]) established a grading system for color and clarity and began using this system in its independent diamond grading laboratory. Today there are many large and small gemological labs world-wide that offer third party diamond grading services. Trade insiders believe that some labs are stricter and more consistent, while other labs are softer (i.e. give higher grades) or may be less consistent. Consequently it is believed the diamond trade adjusts diamond prices based on the lab that issued grading reports.
 
The only published source of price comparison the authors are aware of, between diamonds graded by different labs, is listed on Polishedprices.com:
 
Certificate Calculation factors according to Polishedprices.com
Certificate Factor
AGS 1.028
CGL 1.000
GIA 1.000
HRD 0.981
IGI 0.944
EGL 0.935
NONE 0.935

 
Today’s consumers are learning more about diamonds and pricing. Websites like Pricescope.com and others have contributed to the public's greater knowledge. Many have learned that diamonds graded by GIA-GTL or AGSL[5] are priced at premiums compared to diamonds with reports from other labs. The current study compares lab strictness but importantly, for the first time that the authors are aware of, this survey includes a pricing and value comparison.
 
The prices of a significant quantity of diamonds, more than 50,000, are publicly listed on-line and GIA, EGL USA[6], and AGS graded diamonds were represented in large enough quantities to be included in this study.
 
The reason for a grading lab to give softer grades is to get more business from diamond manufacturers, retailers or wholesalers who want to increase their profits by selling diamonds given higher grades at higher prices. However, EGL USA has claimed recently to have been grading stricter.
 
This survey is the first in a decade[7] that the authors are aware of, was not intended to prove that any lab is better than another. Diamond grading is a subjective art. The consumers should be aware that a grading report is that labs opinion, and not a fact. This was illustrated by the fact that none of the 17 stones were given the same grade for both color and clarity by all 3 labs. One of Pricescope's main intentions with this survey was to compare the relative trading values of diamonds graded by various labs.
 

 

[1] Accredited Gem Appraisers, Philadelphia, PA
[2] Ideal-Scope.com and Precious Metals, Melbourne, Australia
[3] Pricescope.com, Toronto, ON, Canada
[4] The Gemological institute of America (GIA) is recognized world wide and is a not-for-profit organization. However the GIA-Gem Trade Lab is a very profitable business that reinvests its dividends from grading diamonds and gemstones back into gemological education and gem identification and treatment detection research. According to Pricescope' stats, about 73% of all diamonds listed in the Internet are accompanied by GIA-GTL reports. It is a commonly held belief that GIA-GTL grading reports are the strictest in the industry today.
[5] American Gem Society Laboratory (AGSL) jointly owned by the AGS, a not-for-profit organisation, and a group of AGS investor members. It is known for publishing its own diamond round brilliant cut grading system in 1996 which has established it in a niche in the USA diamond market for AGS Zero or "Ideal Cuts". AGSL reports are also regarded as being very strict and consistent. AGSL graded diamonds are only about 5% of all round cut stones listed in the Internet but comprises about 40% of round diamonds cut to today's "ideal" proportions and finish.
[6] Originally EGL had several franchised labs in different countries (Belgium, Israel and USA). Today EGL-USA is privately owned and operates four labs in USA and Canada. About 23% of all diamonds listed in the Internet are graded by European Gemological Laboratories (EGL); EGL and EGL USA listings are included together. EGL USA has a trademark claim in the courts seeking to stop the importation of diamonds with accompanying EGL reports from outside USA. EGL USA claims to have tightened up its grading standards.
[7] JCK magazine ran a survey in the mid 1990's
 
 

Method of Survey

 
This survey was funded by Pricescope, including the expenses of two additional grading reports and shipping of the diamonds. None of the surveyed labs were made aware of the survey.
 
Three labs were surveyed:

  1. GIA-GTL.
  2. AGSL.
  3. EGL USA.
These three labs were chosen because there are reasonable sized commercial data bases of pricing information to enable cost comparisons.
 
Pricescope approached three independent diamond vendors: DirtCheapDiamonds.com, EngagementRingsDirect.com and Whiteflash.com to provide diamonds from their inventories. These stones had already been graded by either GIA-GTL or AGSL and they were then sent to the two other grading laboratories. The vendors were aware of the purpose of this experiment and the need for secrecy. They knew that other vendors would be participating in this survey, but they were not informed of the identity of the other vendors.
 
In total 17 round brilliant cut diamonds were selected for the survey, but one was inadvertently sent to GIA-GTL twice (and received different clarity grades). They ranged from 0.6 -1.25 carat, E – J color and VVS2 – SI2 clarity ranges. The sizes and qualities were chosen to represent frequently traded range of diamonds. The vendors were asked not to deliberately select stones that they considered to be border line examples or stones that in their opinion had been "missgraded". See Appendixes I - V for all diamonds' details.
 
Each of the diamond vendors independently submitted their already lab graded diamonds to two additional grading labs. Namely:
  • tyle="text-decoration: underline">DirtCheapDiamonds.com selected 6 diamonds (5 with AGSL and 1 with GIA-GTL reports) and submitted them to GIA and EGL USA
  • EngagementRingsDirect.coman selected 4 diamonds with GIA-GTL reports and submitted them to AGSL and EGL USA
  • Whiteflash.com selected 7 diamonds with GIA-GTL reports and submitted them to AGSL and EGL USA.

Summary of the results


Diamond grading is not a science; it is a subjective skill. As mentioned, none of the 17 diamonds in this survey was given the same grade for color and clarity by all three laboratories. Due to the subjectivity of human color and clarity grading, it is virtually impossible to say whether one or another grade is absolutely accurate. Instead we decided to consider whether two of the labs grades were stricter or softer compared to GIA-GTL grades. We made this decision because GIA-GTL is the largest lab and is considered as a market leader.
 
To underline the subjectivity of diamond grading it is worth noting that stone #10 already had a 6 month old GIA-GTL report, but was inadvertently resubmitted to GIA-GTL (it was to have been sent to for an AGSL report, which explains its absence). The color was given the same grade, but the clarity on the GIA-GTL report was VS1 on the earlier October 2003 report and VS2 on the April 2004 report. In discussions with the GIA about this particular stone they noted that in their private records on both occasions that it was a border line VS1 / VS2.  The authors chose to include the stone at its softer GIA-GTL grading.
 
 

Relative comparison of the Clarity and Color grades

  Table 1.a. Carat, color and clarity of the diamonds used in the survey
 
 
No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Carat 0.74 0.78 1.08 1.11 0.62 0.60 0.62 0.62 0.71 0.70 0.79 0.71 0.75 1.13 1.02 1.23 0.70
Color
GIA F F H G I I G H H H E E H J E G H
AGS F F G G I H G H H n/a E E H I F G H
EGL E E G F H H F G G G E E G I F G H
Clarity
GIA SI1 VS2 SI2 SI2 VS1 VVS2 VS1 VS2 SI2 VS1 SI1 SI1 SI1 SI2 VVS2 VS1 VS2
AGS SI2 VS2 SI2 SI2 VS2 VVS2 VS2 SI1 SI2 n/a SI2 SI2 SI1 SI1 VS1 VS2 SI1
EGL SI1 VS2 SI2 SI2 VS1 VS1 VS2 VS2 SI2 VS2 SI1 SI2 SI1 SI1 VVS2 VS2 SI1

No. 1
Carat 0.74
Color
GIA F
AGS F
EGL E
Clarity
GIA SI1
AGS SI2
EGL SI1
No. 2
Carat 0.78
Color
GIA F
AGS F
EGL E
Clarity
GIA VS2
AGS VS2
EGL VS2
No. 3
Carat 1.08
Color
GIA H
AGS G
EGL G
Clarity
GIA SI2
AGS SI2
EGL SI2
No. 4
Carat 1.11
Color
GIA G
AGS G
EGL F
Clarity
GIA SI2
AGS SI2
EGL SI2
No. 5
Carat 0.62
Color
GIA I
AGS I
EGL H
Clarity
GIA VS1
AGS VS2
EGL VS1
No. 6
Carat 0.60
Color
GIA I
AGS H
EGL H
Clarity
GIA VVS2
AGS VVS2
EGL VS1
No. 7
Carat 0.62
Color
GIA G
AGS G
EGL F
Clarity
GIA VS1
AGS VS2
EGL VS2
No. 8
Carat 0.62
Color
GIA H
AGS H
EGL G
Clarity
GIA VS2
AGS SI1
EGL VS2
No. 9
Carat 0.71
Color
GIA H
AGS H
EGL G
Clarity
GIA SI2
AGS SI2
EGL SI2
No. 10
Carat 0.70
Color
GIA H
AGS n/a
EGL G
Clarity
GIA VS1
AGS n/a
EGL VS2
No. 11
Carat 0.79
Color
GIA E
AGS E
EGL E
Clarity
GIA SI1
AGS SI2
EGL SI1
No. 12
Carat 0.71
Color
GIA E
AGS E
EGL E
Clarity
GIA SI1
AGS SI2
EGL SI2
No. 13
Carat 0.75
Color
GIA H
AGS H
EGL G
Clarity
GIA SI1
AGS SI1
EGL SI1
No. 14
Carat 1.13
Color
GIA J
AGS I
EGL I
Clarity
GIA SI2
AGS SI1
EGL SI1
No. 15
Carat 1.02
Color
GIA E
AGS F
EGL F
Clarity
GIA VVS2
AGS VS1
EGL VVS2
No. 16
Carat 1.23
Color
GIA G
AGS G
EGL G
Clarity
GIA VS1
AGS VS2
EGL VS2
No. 17
Carat 0.70
Color
GIA H
AGS H
EGL H
Clarity
GIA VS2
AGS SI1
EGL SI1
  Table 1.b. AGSL and EGL USA Grading Compared to GIA-GTL  

  AGSL (out of 16) EGL USA (out of 17)
Clarity Stricter 9 (56%) 6 (35%)
Same 6 (38%) 10 (59%)
Softer 1 (6%) 1 (6%)
Color Stricter 1 (6%) 1 (6%)
Same 12 (75%) 4 (24%)
Softer 3 (19%) 12 (71%)

  fig1.gif Figure 1. Difference in Clarity Grades Compared to GIA-GTL. Below the line corresponds to softer grading (higher grade) and above the line is stricter grading (lower grade) fig2.gif Figure 2. Difference in Color Grade Compared to GIA-GTL. Below the line correspond to softer grading (higher grade) and above the line is stricter grading (lower grade). fig2b.gif fig2c.gif 3.1.1. Stone # 10 GIA Resubmission Difference This diamond already had a GIA-GTL report (Oct. 2003) and was inadvertently resubmitted to GIA-GTL. It was to have been sent for an AGSL report, which explains the absence of AGSL data. The second report (April 2004) received the same color grade but a one grade stricter clarity (VS1 down to VS2). For consistency purposes a comparison was made using the first GIA-GTL report. Other notable differences on these two reports in chronological order were depth percentages of 61.6% to 61.8%, table sizes 57% to 56%, girdle "Medium to Thick" compared to "Medium to Slightly Thick".There was a small dimensions difference: 5.67-5.70x3.50mm compared to 5.67-5.69x3.51mm. The most recent report had a comment "Clouds are not shown". Both plots appear similar. Both sets of proportion data (and that from the EGL USA report) were entered into DiamCalc, the OctoNus diamond modeling software, and it was found that girdle thickness was likely to be on the thicker side of slightly thick for the stones carat weight.  


Cut Grades

Comparison of the contentious issue of cut grades was not possible, since GIA-GTL reports do not rate a diamonds proportion based cut quality. Under the heading ‘Proportions’ are depth percentage, which is the depth divided by average diameter and multiplied by 100, table size as a percentage of the average diameter, the girdle in descriptive wording and finally culet size description. A sub heading ‘Finish’ lists polish and symmetry. Both other labs give crown and pavilion information; AGSL gives both angle and percentage data and EGL USA gives crown height and depth percentages. GIA-GTL noted under comments any diamond with a crown angle greater than 35° or less than 30°. The information provided by AGSL and EGL USA enables proportion grades to be checked with cut grading systems provided by the authors on cutadviser and www.gemappraisers.com. 3.2.1 Proportion Grading AGSL has an optional report system for round diamonds that grades a diamonds cut against a comparatively tight set of proportions. The top grade is ‘zero’ and the worst grade is 10. AGS 0 has become synonymous with the term ‘Ideal Cut’ in North America (stones # 5 to # 10). EGL USA produce optional reports with proportion based cut grade results (e.g. stone # 7 is called EGL IDEAL PLUS). Researchers in the field of cut studies debate the use of parameter ranges for cut grading round diamonds. It would be fair to say that all three labs (and most others) are un-satisfied with the parametric based approach. GIA[1] and AGS[2] now recognize that diamonds with the steepest crown and deepest pavilion, within a cut grade category, are not as attractive as many diamonds of lower grades, with combinations of shallow crown and deep pavilion, or steep crown and shallow pavilion. The same is true for shallowest crown and pavilion combinations. The GIA is conducting a costly decade long cut study to establish a cut grading system. This has taken longer than planned. At the 2004 Basel GemFest GIA released information indicating that its new cut grade system will account for the above mentioned relationship between crown and pavilion angles. 3.2.2 Symmetry and Polish Symmetry and polish were graded for all stones by all three labs. The table below describes the terminology used by each lab.  
GIA-GTL AGSL EGL USA
Excellent Ideal Excellent
Very Good Very Good Very Good
Good Good Good
Fair Fair Fair
Poor Poor Poor
Generally the Polish and Symmetry grades of GIA-GTL and AGSL coincide with each other for Excellent/Ideal and Very Good and Good grades. All three labs gave similar grades for diamonds rated as Good. However EGL USA reported mostly Good or Very Good Polish and Symmetry for diamonds that were graded Excellent / Ideal by GIA-GTL and AGSL respectively.
[1] GIA-GTL presentation at Basel GemFest April 2004 [2] AGSL presentation at the First International Diamond Cut Conference April 2004.


Clarity Plots and Comments

 
A comparison of the diamonds and the plots from all three labs showed that AGSL report plots had a consistency and greater degree of detail than the GIA-GTL reports. The plots of the EGL USA documents were close to the quality of AGSL and contained adequate detail. See Appendix V.
 
GIA-GTL made the most use of comments (12 clarity or surface feature comment on a total of 18 reports), followed by AGSL (10 such comments on 16 reports), however EGL USA made none. GIA-GTL’s stated practice is to plot only the marks that set the clarity grade, with others often being referred to in the comments section; this policy was reflected in the absence of a few inclusions which were reported in the comments section. GIA-GTL plotting was also somewhat less intensely drawn.
 

Laser Inscription

 
Stones # 1 and # 2 both had laser inscriptions noting GIA registry numbers. AGSL noted the both laser inscription numbers on its reports and in one case assigned a stricter clarity grade.
 
EGL USA noted the inscriptions in preliminary grading data faxed to the vendor before printing the reports but did not make a comment on its reports. EGL USA gave both stones a softer color grade.
 


Girdle Thickness

Differences in girdle thickness reporting were slight. See Appendix III. In general, AGSL reports described more detail concerning variation in thickness.
 
 

Measurements and Depth Percentage


All measurements and proportions are shown in Appendix III.
 
Confirming the largest and smallest diameter of a diamond with a micrometer is difficult. This survey did not attempt to check the accuracy of diameter measurements, which are generally reported by a Sarin Technologies scanning device. Diameter variations of 0.01 to 0.03mm were common. Depth measurements varied from none to 0.03mm, with an average of less than 0.02mm. It is a common practice to identify a diamond, or to ensure that a diamond matches its report, by comparing its measurements to those on the certificate.
 
Measurement variations led to inconsistencies in depth percentages, which varied by an average of 0.4% and as much as 0.7% between different laboratories. Depth percentages and table size ratios are used by many buyers to make purchasing decisions; therefore measurement accuracy affects a diamonds market value.
 
 

Pricing

Price analysis was based on the statistics and prices of more than 50,000 unique diamond listings available via the Internet during the first week of July, 2004.
 
3.7.1. Market price adjustment
 
AGSL graded diamonds with Ideal Polish and Symmetry are often priced about 8% - 10% higher than similar GIA-GTL graded diamonds with Excellent/Excellent symmetry and polish. However this differential fluctuates over time and carat weight ranges; a week later than this survey’s analysis period, equivalent GIA-GTL and AGSL listed diamonds in the 0.6-0.69 carat range averaged out at the same price. The relatively small numbers of these stones, and the niche nature of this business, means the various margins of a small number of vendors can have a large effect on the average price results.
 
A number of the diamonds in this survey were not graded as AGS 0 by AGS; these diamonds trade at a lower premium to GIA stones. This has been taken into account in the pricing of these stones.
 
EGL graded diamonds are currently offered within the trade at 9% - 15% lower than the same grade GIA-GTL stones. Our statistics[1] show little (within ±3%) difference in prices for diamonds graded by EGL USA and EGL overseas, although anecdotal evidence suggests a larger differential.
 
Table 2. An example (using stone # 3) of the method used to calculate the market price comparisons in Table 3.

E.g. stone # 3 GIA EGL
Carat 1.08 1.08
Color H G
Clarity SI2 SI2
Number of stones in database 85 54
Avg. Price $4,248 $3,634
Price difference -14%


 


[1] The only way to automatically differentiate listed diamonds graded by EGL USA from EGL in other countries was by the grading report numbers; EGL USA report numbers start with 'LA’, 'US' or '7', or end with 'D'. At the time of this survey there were some 2,500 diamonds in Pricescope database with EGL grading reports that satisfied this condition and about 4,100 listings with EGL reports with numbers that did not. Report numbers were not available for all EGL graded diamonds.
 

Price differences for surveyed diamonds


Table 3. Average cost of all 17 stones based on their grading and the premium or discount[1] that their certificates attract.
Stone # GIA-GTL AGSL EGL USA
Price Price Diff. to GIA Price Diff. to GIA
1 $2,576 $2,296 -11% $2,458 -5%
2 $2,922 $2,922 0% $2,758 -6%
3 $4,248 $4,426 4% $3,634 -14%
4 $4,540 $4,541 0% $3,925 -14%
5 $1,522 $1,456 -4% $1,527 0%
6 $1,496 $1,964 31% $1,478 -1%
7 $2,075 $1,915 -8% $1,707 -18%
8 $1,607 $1,501 -7% $1,569 -2%
9 $2,058 $2,219 8% $1,696 -18%
10 $2,453     $2,212 -10%
11 $2,952 $2,668 -10% $2,624 -11%
12 $2,653 $2,398 -10% $2,103 -21%
13 $2,152 $2,152 0% $2,137 -1%
14 $4,127 $5,907 43% $4,716 14%
15 $8,451 $7,264 -14% $6,739 -20%
16 $8,255 $7,708 -7% $6,323 -23%
17 $2,246 $2,047 -9% $1,892 -16%
Average $3,314 $3,337 1% $2,912 -10%
Stone #
1
GIA-GTL
Price
$2,576
AGSL
Price
$2,296
AGSL
Diff. to GIA
-11%
EGL USA
Price
$2,458
EGL USA
Diff. to GIA
-5%
2
GIA-GTL
Price
$2,922
AGSL
Price
$2,922
AGSL
Diff. to GIA
0%
EGL USA
Price
$2,758
EGL USA
Diff. to GIA
-6%
3
GIA-GTL
Price
$4,248
AGSL
Price
$4,426
AGSL
Diff. to GIA
4%
EGL USA
Price
$3,634
EGL USA
Diff. to GIA
-14%
4
GIA-GTL
Price
$4,540
AGSL
Price
$4,541
AGSL
Diff. to GIA
0%
EGL USA
Price
$3,925
EGL USA
Diff. to GIA
-14%
5
GIA-GTL
Price
$1,522
AGSL
Price
$1,456
AGSL
Diff. to GIA
-4%
EGL USA
Price
$1,527
EGL USA
Diff. to GIA
0%
6
GIA-GTL
Price
$1,496
AGSL
Price
$1,964
AGSL
Diff. to GIA
31%
EGL USA
Price
$1,478
EGL USA
Diff. to GIA
-1%
7
GIA-GTL
Price
$2,075
AGSL
Price
$1,915
AGSL
Diff. to GIA
-8%
EGL USA
Price
$1,707
EGL USA
Diff. to GIA
-18%
8
GIA-GTL
Price
$1,607
AGSL
Price
$1,501
AGSL
Diff. to GIA
-7%
EGL USA
Price
$1,569
EGL USA
Diff. to GIA
-2%
9
GIA-GTL
Price
$2,058
AGSL
Price
$2,219
AGSL
Diff. to GIA
8%
EGL USA
Price
$1,696
EGL USA
Diff. to GIA
-18%
10
GIA-GTL
Price
$2,453
AGSL
Price
 
AGSL
Diff. to GIA
 
EGL USA
Price
$2,212
EGL USA
Diff. to GIA
-10%
11
GIA-GTL
Price
$2,952
AGSL
Price
$2,668
AGSL
Diff. to GIA
-10%
EGL USA
Price
$2,624
EGL USA
Diff. to GIA
-11%
12
GIA-GTL
Price
$2,653
AGSL
Price
$2,398
AGSL
Diff. to GIA
-10%
EGL USA
Price
$2,103
EGL USA
Diff. to GIA
-21%
13
GIA-GTL
Price
$2,152
AGSL
Price
$2,152
AGSL
Diff. to GIA
0%
EGL USA
Price
$2,137
EGL USA
Diff. to GIA
-1%
14
GIA-GTL
Price
$4,127
AGSL
Price
$5,907
AGSL
Diff. to GIA
43%
EGL USA
Price
$4,716
EGL USA
Diff. to GIA
14%
15
GIA-GTL
Price
$8,451
AGSL
Price
$7,264
AGSL
Diff. to GIA
-14%
EGL USA
Price
$6,739
EGL USA
Diff. to GIA
-20%
16
GIA-GTL
Price
$8,255
AGSL
Price
$7,708
AGSL
Diff. to GIA
-7%
EGL USA
Price
$6,323
EGL USA
Diff. to GIA
-23%
17
GIA-GTL
Price
$2,246
AGSL
Price
$2,047
AGSL
Diff. to GIA
-9%
EGL USA
Price
$1,892
EGL USA
Diff. to GIA
-16%
Average
GIA-GTL
Price
$3,314
AGSL
Price
$3,337
AGSL
Diff. to GIA
1%
EGL USA
Price
$2,912
EGL USA
Diff. to GIA
-10%


Price differences compared to similar GIA-GTL graded diamonds.
Figure 3. Price differences compared to similar GIA-GTL graded diamonds. Each positive or negative difference on the chart corresponds to higher or lower prices for similar diamonds listed for sale with respective reports.
 
 
 
Figure 4. 56% of the surveyed diamonds would cost less if sold with AGS rather than GIA reports, mainly as a result of stricter clarity grading 80% of the diamonds would cost less if bought with EGL rather than GIA reports. Discounting of EGL graded diamonds was greater than any premiums as a result of softer color grading.





[1] The premium/discount was calculated from a price study of more than 50,000 diamonds for sale online.
 


Discussion

 
AGSL
 
In 9 out of 16 cases, diamonds with AGSL reports were better deals for buyers, mainly as a result of stricter clarity grades. The average price difference for these 9 stones was 12%. However the average price for all 16 AGSL graded diamonds was 1% more when compared to the prices of the GIA-GTL graded stones because of the large price difference for stones # 6 and # 14.
 
It is most common for diamonds submitted to AGSL to be of or close to AGS 0. Diamonds graded with AGS ‘ideal’ proportions, polish and symmetry (stones # 5 to # 10) can have a premium of about 8% - 10% over the same grade GIA-GTL diamonds (e.g. stone # 9). Because of this premium diamonds with a softer AGSL grading (e.g. stone # 14) would be unfavorable buys. However, diamonds such as # 1 are good deals with AGSL reports because of stricter clarity grading.
 
In the past a myth has spread that GIA-GTL and AGSL exchange information, so that both labs give the same grade. Stones # 1 and # 2 both had laser inscriptions noting GIA registry numbers. AGSL noted the laser inscription numbers on its reports and in one case assigned a stricter clarity grade; in this case the myth of collusion is clearly just a myth.
 
EGL USA
 
Except for stone, # 14, which received a softer grade from both AGSL and EGL USA, buying a diamond based on an EGL USA report would have cost less (or the same in one case) than buying the same diamond with its GIA-GTL report. The market discounts EGL USA graded stones 10% more than the increased prices that result from often softer color grading. This buyer’s advantage holds when there is a small price difference for one grade of color or one grade of clarity. There were savings of about 20% for 5 out of 17 stones; their EGL USA grades matched or were stricter than GIA-GTL grades, or a softer grade was compensated by another stricter one.
 
In the case stone number # 14, buying the EGL USA graded stone would have cost more, but both AGSL and EGL-USA graded this stone more strictly for color and clarity than GIA-GTL. In a business to business (B2B) environment diamonds considered to be wrongly graded are often discounted; stone # 14 sold with its GIA-GTL might be an example. This is one reason why Pricescope.com maintains a list of appraisers and recommends consumers use an independent expert to offer advice when buying a diamond from unknown or un-trusted sources.
 
While EGL USA plots were generally of a high standard, it did not list any comments. Another apparent short coming was inconsistencies in polish and symmetry grading with regard to the other two labs.
 
Lower B2B offer prices for EGL USA graded diamonds indicate that those sending diamonds to EGL USA do so in the belief that they will receive softer grades. However this survey shows that EGL USA actually grades more strictly than many suppliers probably perceive. It is possible that the difficulty in discriminating between EGL USA and EGL graded diamonds, since most B2B sites list only EGL, that vendors submitting diamonds to EGL USA for grading are being undersold.
 
EGL USA has distanced itself from EGL franchises outside of North America, and is currently involved in legal actions to stop the importation of diamonds with EGL reports from predominantly Europe and Israel. It has been suggested softer graded diamonds from EGL labs in other countries have damaged the US organizations reputation. The authors own experience, and anecdotal evidence, support this claim. That said, this survey has found that many industry myths are just that; myths. It is behooves EGL USA to prove their point, and to work towards making it possible for both trade and consumers to more easily identify diamonds that have been graded by EGL USA as opposed to EGL.
 
The lower cost of EGL USA graded diamonds is passed on to consumers who buy on-line from e-tailers who uploaded B2B listings and simply add a set percentage mark-up, the same for all stones. However lower EGL USA grade diamond prices may not always be passed on in full at the retail level. An effective retailer typically prices goods at what the market will bear; it would be reasonable to assume that most consumers would be unaware of the magnitude of the value difference between diamonds with reports from different grading labs. However, even at a retail level, many consumers would be consciously aware of the reputation of the GIA.
 
EGL USA reports can be identified from EGL reports by a clearly displayed 'USA' on the banner at the top. EGL reports from the other ten national franchises do not usually identify where the grading was performed.
 
GIA-GTL
 
The GIA-GTL approach to plotting inclusions showed a slight tendency to more use of 'comments'. Plotting in more detail requires less 'comments' to be noted, and then only for things that cannot be rendered graphically due to their size, relief, quantity, location or marks that might not show up after printing; but plotting in greater detail takes more time. Labs must choose between a plot that might frighten consumers, and the suspicion aroused from listing comments.
 
It is common for consumers on the Pricescope forum to report confusion and suspicion of diamonds with 'comments' listed on a report; this can reduce the diamonds sales prospects or value. On balance the authors feel that plotting with the fewest possible comments and more ploted details would be the most welcomed method for most dealers and retailers.
 

Discussion of Brand Value

In the history of diamonds the demand for certification is a relatively new phenomenon. When GIA-GTL first offered this service in the 1953's the majority of their work was with rare larger diamonds of high color and clarity. Today even diamonds J and lower colors and I2 clarity are often sold with comparatively costly reports; consumers should have no need for a report to judge the acceptability of such diamonds. We may therefore conclude that a diamond grading report itself provides some additional value above and beyond the confidence that the diamond is natural and untreated.

Diamonds are difficult to brand, but considering that a diamond with a GIA report can cost around 10% more than the same diamond with an EGL USA report, this could be a quantification of GIA's brand value. Here are some possible reasons why GIA adds value:

  1. GIA developed the diamond grading standards.
  2. GIA first established independent reporting for diamonds and gems.
  3. The GIA has trained more gemologists and sales people than all other institutes combined.
  4. GIA offers training and education in many foreign countries.
  5. GIA offers effective distance learning programs worldwide.
  6. GIA graduates often prefer to buy and sell diamonds with GIA-GTL reports.
  7. Diamonds graded by GIA-GTL have the excellent re-sale liquidity.
  8. A GIA-GTL graded diamond appears to have the GIA's stamp of approval.

There are, however, some disadvantages associated with GIA-GTL reports.

  1. Additional cost.
  2. No crown and pavilion data for cut quality analysis.
  3. Hence poorly proportioned diamonds are likely to be graded by GIA-GTL.
  4. GIA-GTL reports generally cost more than most other labs.
  5. GIA-GTL takes much longer to grade a diamond than other labs.

Diamonds with AGSL reports command the same or slightly higher prices as GIA-GTL graded diamonds. The market perceives a high level of trust in AGSL color and clarity grading; however their reputation has more to do with AGS being the “ideal cut” brand. Rarely are there diamonds listed for sale that are not AGS 0 or AGS 1. The terms 'ideal-cut' and AGS 0 have become synonymous.
 
EGL USA works very hard at building its brand through advertising and promotion. To this end EGL USA has attempted, through legal channels, to stop the entry into USA and Canada of diamonds accompanied by EGL reports from outside the Americas. If EGL USA does grade more strictly than EGL in other countries, then diamonds with imported certificates would damage their brand. Differentiating their certificates on B2B listings would seem to be a priority for EGL USA to improve its brand standing. However, further tightening of EGL USA’s grading strictness is a double edged sword; that might result in a reduction in the number of diamonds being submitted.

 

Independent Appraisal

With the publication of this report, consumers buying on-line may feel more need for the services of an independent expert when purchasing a meaningful diamond. Traditionally this was the role of a retailer; to provide consumers with a safe and secure shopping service. Relying on grading reports is not a 'carte blanche' without seeing the diamond is not good for anyone in the trade, so it cannot be different for consumers who do not have the expertise to make their own assessment of color, clarity, cut, and light behavior. Many will continue to look for outside assistance of the type provided by one of the authors, Mr Dave Atlas, who has been active in advising consumers for many years, even long before the Internet. The Pricescope experience shows that many 'diamond junky' consumers know more about diamonds than those working within the industry; hardly surprising given that diamonds are such a desirable product. The vast amounts of collected information and expert advice on Pricescope feeds 'diamond junkies' minds, as well as those of participating industry experts; those experts and retailers often agree that they have learned a lot on the PriceScope Forum. It seems that the more a consumers knows, the more need they seem to have for an independent appraisals. New diamond consumers, armed with a wealth of information and sometimes an Ideal-Scope, are often better informed than the staff behind jewelry store counters. Many of these consumers have raised expectations. Pricescope wants to help retailers learn to deal with this new type of customer. One way is to develop a 'voice' on Internet Forums; giving freely of their expertise engenders trust and will ensure they thrive. Many of those unwilling to up-skill in this Internet led information revolution will go the way of the dinosaur.



Conclusion

 
"Diamond Prices and Grading Q&A Forum" is the title of PriceScope's Forum. This surveys aim was to demystify diamond pricing, not to endorse or to damage any lab. The findings of the market pricing component of this survey were based on a large statistically sound population, but used only 16 or 17 stones for lab grading comparisons. The lab grades did however confirm some of the market myths, such as EGL USA color grades can be softer and AGSL clarity grades can be stricter than GIA-GTL. However, we found no support for reports of EGL USA color grading being more than one grade different to the other labs. In fact all lab grades were within a single grade of difference for color or clarity. The most interesting finding was that softest average grading did not lead to a higher average buying price.
 
One dealers myth is: "One must buy the diamond, not the paper", however we found the B2B marketplace adjusts pricing for its expectation for grading strictness. But does the retail market pass on those price differences? Perhaps this is a separate survey for the future?
 
Pricescope initiated this survey to clarify diamond grading myths and facts which are passed on via public Pricescope forum from diamontaires, appraisers and retail jewelers to consumers. As advocates for the diamond buying public, Pricescope strives to demystify diamond buying for the public in the belief that helping people buy diamonds will grow diamond sales. Many in the industry consider the idea of educating consumers heretical, but as a leading industry figure, Martin Rapaport, said: "If the educated consumer is your nightmare, then go out of business. Consumers won't get less educated." Pricescope estimates that more than 80% of the money spent on larger diamonds in USA follows some research on the Internet.
 
After reading this article, many consumers will feel safer buying a diamond graded by the market leader, GIA. Others might be willing to trade brand value for a lower cost EGL USA graded diamond. Yet another person may be attracted by the stricter AGSL grading. Consumers who learn about this survey may drive a harder bargain for an EGL USA graded diamond in retail stores.
 
Myth and Facts
  • “Diamonds graded by GIA-GTL have better resale liquidity”. Fact
  • "GIA is the strictest laboratory in the world" – Myth. According to this survey 8 out of 16 diamonds were graded more strictly by AGS. EGL tended to grade clarity more strictly.
  • "AGS is very strict" – A fact overall, but AGSL color grades can be softer than GIA-GTL.
  • "EGL certificates are not worth the paper they are printed on" – Myth. Although in 12 cases out of 17 EGL graded color softer, EGL clarity grading was as strict or stricter as GIA.
  • "GIA has the strongest international diamond brand" - Fact.
  • "It is safer to buy a GIA graded diamond" - Myth. Any diamond grading report is an opinion, not a guarantee.
  • "GIA invented the grading standards and independent reports"- Fact.
  • "GIA or AGS reports guarantee grading accuracy" – Myth. This survey shows that both labs can grade either softer or more strictly and this affects a diamonds price.
  • "Consumers should consider an appraisal by a qualified and independent gemologist" – Fact. This can ensure a diamond meets a consumers criteria and to avoid possible switching errors (two occurred in this survey).
  • "Diamonds with GIA reports trade for higher prices". Myth - AGSL diamonds often trade for more.
  • "GIA has trained more gemologists world-wide than all the other schools combined" - Fact.
  • "Excellent / Excellent GIA graded diamonds are more beautiful" – Myth. An Ex / Ex diamond can have poor proportions; symmetry and polish have less effect on diamond beauty than proportions.
  • "GIA-GTL charges more than other labs" – Fact. This adds to the cost.
  • "GIA-GTL takes longer to grade a diamond than other labs". Fact - This adds to the cost.
  • "GIA-GTL provides the least useful cut grading information of any major lab" - Fact
  • "You can get ripped off buying an EGL USA graded diamond" - Myth. Even if you buy a one higher color EGL graded diamond than you require, GIA-GTL may grade it a color grade lower and the same clarity, but you will probably pay less.
Over time labs may adjust their grading strictness, and new myths and market pricing may evolve. For this reason Pricescope will regularly conduct similar surveys of these and other diamond grading laboratories.
 
Consistency
 
One initial aims of this survey was to compare grading consistency; this was not an easy task. To compare consistency a bench mark is needed; the question is to which benchmark should consistency be compared? The industry generally looks to the GIA-GTL as the standard or benchmark of diamond grading. However GIA-GTL also gave a different grade for the same stone (# 10). While EGL USA was softer with color grading, it was consistently softer. However, a 16 or 17 stone survey is too small to draw any conclusions on consistency.
 

Acknowledgements

We wish to acknowledge the help and assistance provided by DirtCheapDiamonds.com EngagementRingsDirect.com and Whiteflash.com whose valuable merchandise was unavailable for sale for a considerable period, and for the administrative work involved in shipping and collating information. Without their help and involvement, we could not have performed this survey. We are also grateful to Mr. P. Yantzer, the Director of AGSL, Mr. B. Boyajian, the President of GIA, and Mr. M. Gershburg, the Director of EGL USA, for their help in verifying the data presented in this article and constructive criticism.



Appendix I. Diamond Grading Reports

 
 

Diamond No. Report 1 Report 2 Report 3
1 GIA 10980447 AGS 0005083801 EGL US 29659903D
2 GIA 12067698 AGS 0005083802 EGL US 29659904D
3 GIA 11600572 AGS 0005083804 EGL US 29659902D
4 GIA 11078850 AGS 0005083803 EGL US 29659901D
5 GIA 13359870 AGS 0004843410 EGL US 29809205D
6 GIA 13359793 AGS 0004416606 EGL US 29809204D
7 GIA 13359854 AGS 0004843309 EGL US 29809206D
8 GIA 13359814 AGS 0003935809 EGL US 29809203D
9 GIA 13359863 AGS 0004819808 EGL US 29809202D
10 GIA 12911597 GIA 13359789 EGL US 29809201D
11 GIA 12094476 AGS 0005129801 EGL US 30248507D
12 GIA 12243841 AGS 0005129802 EGL US 30248505D
13 GIA 12137092 AGS 0005129804 EGL US 30248501D
14 GIA 13146918 AGS 0005129805 EGL US 30248502D
15 GIA 12910179 AGS 0005129806 EGL US 30248506D
16 GIA 11937949 AGS 0005129807 EGL US 30248503D
17 GIA 12243850 AGS 0005129803 EGL US 30248504D
Diamond No.
1
Report 1GIA 10980447
Report 2AGS 0005083801
Report 3EGL US 29659903D
2
Report 1GIA 12067698
Report 2AGS 0005083802
Report 3EGL US 29659904D
3
Report 1GIA 11600572
Report 2AGS 0005083804
Report 3EGL US 29659902D
4
Report 1GIA 11078850
Report 2AGS 0005083803
Report 3EGL US 29659901D
5
Report 1GIA 13359870
Report 2AGS 0004843410
Report 3EGL US 29809205D
6
Report 1GIA 13359793
Report 2AGS 0004416606
Report 3EGL US 29809204D
7
Report 1GIA 13359854
Report 2AGS 0004843309
Report 3EGL US 29809206D
8
Report 1GIA 13359814
Report 2AGS 0003935809
Report 3EGL US 29809203D
9
Report 1GIA 13359863
Report 2AGS 0004819808
Report 3EGL US 29809202D
10
Report 1GIA 12911597
Report 2GIA 13359789
Report 3EGL US 29809201D
11
Report 1GIA 12094476
Report 2AGS 0005129801
Report 3EGL US 30248507D
12
Report 1GIA 12243841
Report 2AGS 0005129802
Report 3EGL US 30248505D
13
Report 1GIA 12137092
Report 2AGS 0005129804
Report 3 EGL US 30248501D
14
Report 1GIA 13146918
Report 2AGS 0005129805
Report 3EGL US 30248502D
15
Report 1GIA 12910179
Report 2AGS 0005129806
Report 3EGL US 30248506D
16
Report 1GIA 11937949
Report 2AGS 0005129807
Report 3EGL US 30248503D
17
Report 1GIA 12243850
Report 2AGS 0005129803
Report 3EGL US 30248504D

 

Appendix II. Carat, Color, and Clarity


No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Carat
GIA .74 .78 1.08 1.11 .62 .60 .62 .62 .71 .70 .79 .71 .75 1.13 1.02 1.23 .70
AGS .744 .787 1.082 1.110 .623 .606 .620 .621 .716   .797 .711 .750 1.136 1.020 1.234 .702
EGL .74 .78 1.08 1.11 .62 .60 .62 .62 .71 .70 .79 .71 .75 1.13 1.02 1.23 .70
Color
GIA F F H G I I G H H H E E H J E G H
AGS F F G G I H G H H   E E H I F G H
EGL E E G F H H F G G G E E G I F G H
Clarity
GIA SI1 VS2 SI2 SI2 VS1 VVS2 VS1 VS2 SI2 VS1 SI1 SI1 SI1 SI2 VVS2 VS1 VS2
AGS SI2 VS2 SI2 SI2 VS2 VVS2 VS2 SI1 SI2   SI2 SI2 SI1 SI1 VS1 VS2 SI1
EGL SI1 VS2 SI2 SI2 VS1 VS1 VS2 VS2 SI2 VS2 SI1 SI2 SI1 SI1 VVS2 VS2 SI1
No.1
Carat
GIA.74
AGS.744
EGL.74
Color
GIAF
AGSF
EGLE
Clarity
GIASI1
AGSSI2
EGLSI1
No.2
Carat
GIA.78
AGS.787
EGL.78
Color
GIAF
AGSF
EGLE
Clarity
GIAVS2
AGSVS2
EGLVS2
No.3
Carat
GIA1.08
AGS1.082
EGL1.08
Color
GIAH
AGSG
EGLG
Clarity
GIASI2
AGSSI2
EGLSI2
No.4
Carat
GIA1.11
AGS1.110
EGL1.11
Color
GIAG
AGSG
EGLF
Clarity
GIASI2
AGSSI2
EGLSI2
No.5
Carat
GIA.62
AGS.623
EGL.62
Color
GIAI
AGSI
EGLH
Clarity
GIAVS1
AGSVS2
EGLVS1
No.6
Carat
GIA.60
AGS.606
EGL.60
Color
GIAI
AGSH
EGLH
Clarity
GIAVVS2
AGSVVS2
EGLVS1
No.7
Carat
GIA.62
AGS.620
EGL.62
Color
GIAG
AGSG
EGLF
Clarity
GIAVS1
AGSVS2
EGLVS2
No.8
Carat
GIA.62
AGS.621
EGL.62
Color
GIAH
AGSH
EGLG
Clarity
GIAVS2
AGSSI1
EGLVS2
No.9
Carat
GIA.71
AGS.716
EGL.71
Color
GIAH
AGSH
EGLG
Clarity
GIASI2
AGSSI2
EGLSI2
No.10
Carat
GIA.70
AGS 
EGL.70
Color
GIAH
AGS 
EGLG
Clarity
GIAVS1
AGS 
EGLVS2
No.11
Carat
GIA.79
AGS.797
EGL.79
Color
GIAE
AGSE
EGLE
Clarity
GIASI1
AGSSI2
EGLSI1
No.12
Carat
GIA.71
AGS.711
EGL.71
Color
GIAE
AGSE
EGLE
Clarity
GIASI1
AGSSI2
EGLSI2
No.13
Carat
GIA.75
AGS.750
EGL.75
Color
GIAH
AGSH
EGLG
Clarity
GIASI1
AGSSI1
EGLSI1
No.14
Carat
GIA1.13
AGS1.136
EGL1.13
Color
GIAJ
AGSI
EGLI
Clarity
GIASI2
AGSSI1
EGLSI1
No.15
Carat
GIA1.02
AGS1.020
EGL1.02
Color
GIAE
AGSF
EGLF
Clarity
GIAVVS2
AGSVS1
EGLVVS2
No.16
Carat
GIA1.23
AGS1.234
EGL1.23
Color
GIAG
AGSG
EGLG
Clarity
GIAVS1
AGSVS2
EGLVS2
No.17
Carat
GIA.70
AGS.702
EGL.70
Color
GIAH
AGSH
EGLH
Clarity
GIAVS2
AGSSI1
EGLSI1



Appendix III. Proportions and Measurements


 

No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Total Depth %
GIA 63 59.8 60.6 62.2 61.9 61.9 61.5 61.5 60.9 61.8 63.0 62.8 61.5 60.4 61.2 56.9 63.0
AGS 63.2 60.1 60.8 62.6 61.8 61.8 61.4 61.2 60.8   63.0 63.4 61.6 60.8 61.4 57.3 63.4
EGL 63.1 60.4 60.7 62.4 62.3 62.1 61.8 61.9 61.1 62 63.3 63.3 61.8 60.8 61.5 57.4 63.5

Table %
GIA 55 60 61 59 53 54 56 57 57 56/57 59 58 60 56 54 62 54
AGS 54 59 60 59 54 55 57 57 57   59 58 60 55 54 61 54
EGL 54 58 60 58 54 54 56 57 57 56 59 58 60 56 53 62 54

Girdle
GIA Med
-
S.Thk
F
Med


F
Thn
-
Med
F
Thn
-
Med
F
Med


F
Thn
-
Med
F
Med


F
Thn
-
Med
F
Thn


F
Med
-
S.Thk
F
S.Thk


F
Thn
-
Thk
F
Med
-
S.Thk
Thn Med Thn
-
Med
F
Med
-
Thk
F
AGS Med
-
Thk
F
Thn
-
S.Thk
F
Thn
-
S.Thk
F
V.Thn
-
Med
F
0.9%
-
2.0%
F
0.7%
-
1.5%
F
1.5%
-
2.2%
0.7%
-
1.5%
F
0.7%
-
1.2%
F
  S.Thk


F
Thn
-
Thk
F
Med
-
Thk
Thn Thn
-
Med
Thn
-
Med
F
S.Thk
-
Thk, F
EGL Med
-
S.Thk
F
Med


F
V.Thn
-
Thn
V.Thn
-
Thn
Thn


F
Thn


F
Thn
-
med
F
0.7%
-
1.3%
Thn


F
Thn
-
Med
F
S.Thk


F
X.Thn
-
S.Thk
F
Med
-
S.Thk
SF
Thn Med
-
S.Thk
Thn
-
Med
F
S.Thk
-
Thk
F

Diameter Min (mm)
GIA 5.72 6.00 6.63 6.58 5.49 5.43 5.44 5.48 5.78 5.67 5.86 5.63 5.79 6.79 6.50 7.15 5.62
AGS 5.71 5.99 6.64 6.59 5.50 5.43 5.45 5.5 5.79   5.87 5.62 5.79 6.79 6.50 7.14 5.62
EGL 5.71 5.99 6.63 6.58 5.47 5.41 5.43 5.47 5.76 5.65 5.85 5.60 5.77 6.77 6.49 7.13 5.61

Diameter Max (mm)
GIA 5.81 6.05 6.68 6.63 5.52 5.46 5.48 5.51 5.81 5.69 5.92 5.70 5.85 6.82 6.60 7.19 5.65
AGS 5.81 6.05 6.7 6.63 5.54 5.47 5.49 5.52 5.82   5.92 5.69 5.87 6.80 6.59 7.18 5.65
EGL 5.78 6.03 6.68 6.62 5.51 5.45 5.46 5.51 5.8 5.67 5.91 5.67 5.88 6.81 6.59 7.16 5.66

Total Depth (mm)
GIA 3.63 3.6 4.03 4.11 3.41 3.37 3.36 3.38 3.53 3.51 3.71 3.56 3.58 4.11 4.01 4.08 3.55
AGS 3.61 3.62 4.05 4.14 3.41 3.37 3.36 3.37 3.53
3.71 3.58 3.59 4.13 4.02 4.10 3.57
EGL 3.63 3.63 4.04 4.12 3.42 3.37 3.37 3.39 3.54 3.51 3.72 3.57 3.59 4.12 4.02 4.10 3.57

Pavilion Angle
AGS 40.8 41.4
41.3 41.1 40.9 40.8 41.1 41
41.8 41.2 41.5 40.9 41.1 41.1 40.9
EGL               41.2                  

Pavilion Depth %
AGS 42.9 43.7 44.3 43.6 43.3 43.1 43.0 43.4 43.2   44.3 43.4 43.9 43.2 43.4 43.4 43.2
EGL 42.8 44.3 44.3 43.5 43.5 43.3 43.1 43.8 43.5 42.8 44.6 43.4 44.1 43.2 43.6 43.7 43.2

Crown Angle
AGS 35.4 32.3 33.2 34.5 34.0 34.4 34.3 34.2 34.1   35.9 37.2 34.3 34.9 33.7 29.7 34.7
EGL               34.4                  

Crown Height %
AGS 16.3 13   14.2 15.6 15.4 14.8 14.5 14.5   14.8 15.8 13.7 15.5 15.3 11.0 15.8
EGL 16.5 13.1 13.2 14.5 15.7 15.7 14.9 14.8 14.7 14.8 14.8 16.0 13.9 15.5 15.4 10.9 16.0

Culet
GIA N N N N N N N N N N N N N N N N N
AGS P P P P P P P P P   P P P P P P P
EGL N N N N N N N N N N N N N N N N N

No 1
Total Depth %
GIA 63
AGS 63.2
EGL 63.1
Table %
GIA 55
AGS 54
EGL 54
Girdle
GIA Med
-
S.Thk
F
AGS Med
-
Thk
F
EGL Med
-
S.Thk
F
Diameter Min (mm)
GIA 5.72
AGS 5.71
EGL 5.71
Diameter Max (mm)
GIA 5.81
AGS 5.81
EGL 5.78
Total Depth (mm)
GIA 3.63
AGS 3.61
EGL 3.63
Pavilion Angle
AGS 40.8
EGL  
Pavilion Depth %
AGS 42.9
EGL 42.8
Crown Angle
AGS 35.4
EGL  
Crown Height %
AGS 16.3
EGL 16.5
Culet
GIA N
AGS P
EGL N
No 2
Total Depth %
GIA 59.8
AGS 60.1
EGL 60.4
Table %
GIA 60
AGS 59
EGL 58
Girdle
GIA Med


F
AGS Thn
-
S.Thk
F
EGL Med


F
Diameter Min (mm)
GIA 6.00
AGS 5.99
EGL 5.99
Diameter Max (mm)
GIA 6.05
AGS 6.05
EGL 6.03
Total Depth (mm)
GIA 3.6
AGS 3.62
EGL 3.63
Pavilion Angle
AGS 41.4
EGL  
Pavilion Depth %
AGS 43.7
EGL 44.3
Crown Angle
AGS 32.3
EGL  
Crown Height %
AGS 13
EGL 13.1
Culet
GIA N
AGS P
EGL N
No 3
Total Depth %
GIA 60.6
AGS 60.8
EGL 60.7
Table %
GIA 61
AGS 60
EGL 60
Girdle
GIA Thn
-
Med
F
AGS Thn
-
S.Thk
F
EGL V.Thn
-
Thn
Diameter Min (mm)
GIA 6.63
AGS 6.64
EGL 6.63
Diameter Max (mm)
GIA 6.68
AGS 6.7
EGL 6.68
Total Depth (mm)
GIA 4.03
AGS 4.05
EGL 4.04
Pavilion Angle
AGS
EGL  
Pavilion Depth %
AGS 44.3
EGL 44.3
Crown Angle
AGS 33.2
EGL  
Crown Height %
AGS  
EGL 13.2
Culet
GIA N
AGS P
EGL N
No 4
Total Depth %
GIA 62.2
AGS 62.6
EGL 62.4
Table %
GIA 59
AGS 59
EGL 58
Girdle
GIA Thn
-
Med
F
AGS V.Thn
-
Med
F
EGL V.Thn
-
Thn
Diameter Min (mm)
GIA 6.58
AGS 6.59
EGL 6.58
Diameter Max (mm)
GIA 6.63
AGS 6.63
EGL 6.62
Total Depth (mm)
GIA 4.11
AGS 4.14
EGL 4.12
Pavilion Angle
AGS 41.3
EGL  
Pavilion Depth %
AGS 43.6
EGL 43.5
Crown Angle
AGS 34.5
EGL  
Crown Height %
AGS 14.2
EGL 14.5
Culet
GIA N
AGS P
EGL N
No 5
Total Depth %
GIA 61.9
AGS 61.8
EGL 62.3
Table %
GIA 53
AGS 54
EGL 54
Girdle
GIA Med


F
AGS 0.9%
-
2.0%
F
EGL Thn


F
Diameter Min (mm)
GIA 5.49
AGS 5.50
EGL 5.47
Diameter Max (mm)
GIA 5.52
AGS 5.54
EGL 5.51
Total Depth (mm)
GIA 3.41
AGS 3.41
EGL 3.42
Pavilion Angle
AGS 41.1
EGL  
Pavilion Depth %
AGS 43.3
EGL 43.5
Crown Angle
AGS 34.0
EGL  
Crown Height %
AGS 15.6
EGL 15.7
Culet
GIA N
AGS P
EGL N
No 6
Total Depth %
GIA 61.9
AGS 61.8
EGL 62.1
Table %
GIA 54
AGS 55
EGL 54
Girdle
GIA Thn
-
Med
F
AGS 0.7%
-
1.5%
F
EGL Thn


F
Diameter Min (mm)
GIA 5.43
AGS 5.43
EGL 5.41
Diameter Max (mm)
GIA 5.46
AGS 5.47
EGL 5.45
Total Depth (mm)
GIA 3.37
AGS 3.37
EGL 3.37
Pavilion Angle
AGS 40.9
EGL  
Pavilion Depth %
AGS 43.1
EGL 43.3
Crown Angle
AGS 34.4
EGL  
Crown Height %
AGS 15.4
EGL 15.7
Culet
GIA N
AGS P
EGL N
No 7
Total Depth %
GIA 61.5
AGS 61.4
EGL 61.8
Table %
GIA 56
AGS 57
EGL 56
Girdle
GIA Med


F
AGS 1.5%
-
2.2%
EGL Thn
-
med
F
Diameter Min (mm)
GIA 5.44
AGS 5.45
EGL 5.43
Diameter Max (mm)
GIA 5.48
AGS 5.49
EGL 5.46
Total Depth (mm)
GIA 3.36
AGS 3.36
EGL 3.37
Pavilion Angle
AGS 40.8
EGL  
Pavilion Depth %
AGS 43.0
EGL 43.1
Crown Angle
AGS 34.3
EGL  
Crown Height %
AGS 14.8
EGL 14.9
Culet
GIA N
AGS P
EGL N
No 8
Total Depth %
GIA 61.5
AGS 61.2
EGL 61.9
Table %
GIA 57
AGS 57
EGL 57
Girdle
GIA Thn
-
Med
F
AGS 0.7%
-
1.5%
F
EGL 0.7%
-
1.3%
Diameter Min (mm)
GIA 5.48
AGS 5.5
EGL 5.47
Diameter Max (mm)
GIA 5.51
AGS 5.52
EGL 5.51
Total Depth (mm)
GIA 3.38
AGS 3.37
EGL 3.39
Pavilion Angle
AGS 41.1
EGL 41.2
Pavilion Depth %
AGS 43.4
EGL 43.8
Crown Angle
AGS 34.2
EGL 34.4
Crown Height %
AGS 14.5
EGL 14.8
Culet
GIA N
AGS P
EGL N
No 9
Total Depth %
GIA 60.9
AGS 60.8
EGL 61.1
Table %
GIA 57
AGS 57
EGL 57
Girdle
GIA Thn


F
AGS 0.7%
-
1.2%
F
EGL Thn


F
Diameter Min (mm)
GIA 5.78
AGS 5.79
EGL 5.76
Diameter Max (mm)
GIA 5.81
AGS 5.82
EGL 5.8
Total Depth (mm)
GIA 3.53
AGS 3.53
EGL 3.54
Pavilion Angle
AGS 41
EGL  
Pavilion Depth %
AGS 43.2
EGL 43.5
Crown Angle
AGS 34.1
EGL  
Crown Height %
AGS 14.5
EGL 14.7
Culet
GIA N
AGS P
EGL N
No 10
Total Depth %
GIA 61.8
AGS  
EGL 62
Table %
GIA 56/57
AGS  
EGL 56
Girdle
GIA Med
-
S.Thk
F
AGS  
EGL Thn
-
Med
F
Diameter Min (mm)
GIA 5.67
AGS  
EGL 5.65
Diameter Max (mm)
GIA 5.69
AGS  
EGL 5.67
Total Depth (mm)
GIA 3.51
AGS
EGL 3.51
Pavilion Angle
AGS
EGL  
Pavilion Depth %
AGS  
EGL 42.8
Crown Angle
AGS  
EGL  
Crown Height %
AGS  
EGL 14.8
Culet
GIA N
AGS  
EGL N
No 11
Total Depth %
GIA 63.0
AGS 63.0
EGL 63.3
Table %
GIA 59
AGS 59
EGL 59
Girdle
GIA S.Thk


F
AGS S.Thk


F
EGL S.Thk


F
Diameter Min (mm)
GIA 5.86
AGS 5.87
EGL 5.85
Diameter Max (mm)
GIA 5.92
AGS 5.92
EGL 5.91
Total Depth (mm)
GIA 3.71
AGS 3.71
EGL 3.72
Pavilion Angle
AGS 41.8
EGL  
Pavilion Depth %
AGS 44.3
EGL 44.6
Crown Angle
AGS 35.9
EGL  
Crown Height %
AGS 14.8
EGL 14.8
Culet
GIA N
AGS P
EGL N
No 12
Total Depth %
GIA 62.8
AGS 63.4
EGL 63.3
Table %
GIA 58
AGS 58
EGL 58
Girdle
GIA Thn
-
Thk
F
AGS Thn
-
Thk
F
EGL X.Thn
-
S.Thk
F
Diameter Min (mm)
GIA 5.63
AGS 5.62
EGL 5.60
Diameter Max (mm)
GIA 5.70
AGS 5.69
EGL 5.67
Total Depth (mm)
GIA 3.56
AGS 3.58
EGL 3.57
Pavilion Angle
AGS 41.2
EGL  
Pavilion Depth %
AGS 43.4
EGL 43.4
Crown Angle
AGS 37.2
EGL  
Crown Height %
AGS 15.8
EGL 16.0
Culet
GIA N
AGS P
EGL N
No 13
Total Depth %
GIA 61.5
AGS 61.6
EGL 61.8
Table %
GIA 60
AGS 60
EGL 60
Girdle
GIA Med
-
S.Thk
AGS Med
-
Thk
EGL Med
-
S.Thk
SF
Diameter Min (mm)
GIA 5.79
AGS 5.79
EGL 5.77
Diameter Max (mm)
GIA 5.85
AGS 5.87
EGL 5.88
Total Depth (mm)
GIA 3.58
AGS 3.59
EGL 3.59
Pavilion Angle
AGS 41.5
EGL  
Pavilion Depth %
AGS 43.9
EGL 44.1
Crown Angle
AGS 34.3
EGL  
Crown Height %
AGS 13.7
EGL 13.9
Culet
GIA N
AGS P
EGL N
No 14
Total Depth %
GIA 60.4
AGS 60.8
EGL 60.8
Table %
GIA 56
AGS 55
EGL 56
Girdle
GIA Thn
AGS Thn
EGL Thn
Diameter Min (mm)
GIA 6.79
AGS 6.79
EGL 6.77
Diameter Max (mm)
GIA 6.82
AGS 6.80
EGL 6.81
Total Depth (mm)
GIA 4.11
AGS 4.13
EGL 4.12
Pavilion Angle
AGS 40.9
EGL  
Pavilion Depth %
AGS 43.2
EGL 43.2
Crown Angle
AGS 34.9
EGL  
Crown Height %
AGS 15.5
EGL 15.5
Culet
GIA N
AGS P
EGL N
No 15
Total Depth %
GIA 61.2
AGS 61.4
EGL 61.5
Table %
GIA 54
AGS 54
EGL 53
Girdle
GIA Med
AGS Thn
-
Med
EGL Med
-
S.Thk
Diameter Min (mm)
GIA 6.50
AGS 6.50
EGL 6.49
Diameter Max (mm)
GIA 6.60
AGS 6.59
EGL 6.59
Total Depth (mm)
GIA 4.01
AGS 4.02
EGL 4.02
Pavilion Angle
AGS 41.1
EGL  
Pavilion Depth %
AGS 43.4
EGL 43.6
Crown Angle
AGS 33.7
EGL  
Crown Height %
AGS 15.3
EGL 15.4
Culet
GIA N
AGS P
EGL N
No 16
Total Depth %
GIA 56.9
AGS 57.3
EGL 57.4
Table %
GIA 62
AGS 61
EGL 62
Girdle
GIA Thn
-
Med
F
AGS Thn
-
Med
F
EGL Thn
-
Med
F
Diameter Min (mm)
GIA 7.15
AGS 7.14
EGL 7.13
Diameter Max (mm)
GIA 7.19
AGS 7.18
EGL 7.16
Total Depth (mm)
GIA 4.08
AGS 4.10
EGL 4.10
Pavilion Angle
AGS 41.1
EGL  
Pavilion Depth %
AGS 43.4
EGL 43.7
Crown Angle
AGS 29.7
EGL  
Crown Height %
AGS 11.0
EGL 10.9
Culet
GIA N
AGS P
EGL N
No 17
Total Depth %
GIA 63.0
AGS 63.4
EGL 63.5
Table %
GIA 54
AGS 54
EGL 54
Girdle
GIA Med
-
Thk
F
AGS S.Thk
-
Thk, F
EGL S.Thk
-
Thk
F
Diameter Min (mm)
GIA 5.62
AGS 5.62
EGL 5.61
Diameter Max (mm)
GIA 5.65
AGS 5.65
EGL 5.66
Total Depth (mm)
GIA 3.55
AGS 3.57
EGL 3.57
Pavilion Angle
AGS 40.9
EGL  
Pavilion Depth %
AGS 43.2
EGL 43.2
Crown Angle
AGS 34.7
EGL  
Crown Height %
AGS 15.8
EGL 16.0
Culet
GIA N
AGS P
EGL N

Abbreviations
Girdle
X.Thn - Extremely Thin
V.Thn - Very Thin
Thn - Thin
Med - Medium
S.Thk - Slightly Thick
Thk - Thick
F - Faceted
Culet
N - None
P - Pointed

 


 

Appendix IV. Finish and Fluorescence

 
No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Polish
GIA VG VG G G EX EX EX EX EX EX VG VG G EX VG VG VG
AGS VG VG G G ID ID ID ID ID   VG G G EX VG VG VG
EGL VG VG G G G G G VG G G VG G G VG G G G

Symmetry
GIA G G G G EX EX EX EX EX EX VG G G EX G G VG
AGS G G G G ID ID ID ID ID   VG G VG EX EX G EX
EGL VG VG G G G G G VG G G G G G VG VG G VG

Fluorescence
GIA No No No No No No No No No No No No No No Ft No No
AGS Ng Ng Ng Ng Ng Ng Ng Ng Ng   Ng Ng Ng Ng Ng Ng Ng
EGL No No No No No No No No No No No Ft No No Ft No No


No 1
Polish
GIA VG
AGS VG
EGL VG
Symmetry
GIA G
AGS G
EGL VG
Fluorescence
GIA No
AGS Ng
EGL No
No 2
Polish
GIA VG
AGS VG
EGL VG
Symmetry
GIA G
AGS G
EGL VG
Fluorescence
GIA No
AGS Ng
EGL No
No 3
Polish
GIA G
AGS G
EGL G
Symmetry
GIA G
AGS G
EGL G
Fluorescence
GIA No
AGS Ng
EGL No
No 4
Polish
GIA G
AGS G
EGL G
Symmetry
GIA G
AGS G
EGL G
Fluorescence
GIA No
AGS Ng
EGL No
No 5
Polish
GIA EX
AGS ID
EGL G
Symmetry
GIA EX
AGS ID
EGL G
Fluorescence
GIA No
AGS Ng
EGL No
No 6
Polish
GIA EX
AGS ID
EGL G
Symmetry
GIA EX
AGS ID
EGL G
Fluorescence
GIA No
AGS Ng
EGL No
No 7
Polish
GIA EX
AGS ID
EGL G
Symmetry
GIA EX
AGS ID
EGL G
Fluorescence
GIA No
AGS Ng
EGL No
No 8
Polish
GIA EX
AGS ID
EGL VG
Symmetry
GIA EX
AGS ID
EGL VG
Fluorescence
GIA No
AGS Ng
EGL No
No 9
Polish
GIA EX
AGS ID
EGL G
Symmetry
GIA EX
AGS ID
EGL G
Fluorescence
GIA No
AGS Ng
EGL No
No 10
Polish
GIA EX
AGS  
EGL G
Symmetry
GIA EX
AGS  
EGL G
Fluorescence
GIA No
AGS  
EGL No
No 11
Polish
GIA VG
AGS VG
EGL VG
Symmetry
GIA VG
AGS VG
EGL G
Fluorescence
GIA No
AGS Ng
EGL No
No 12
Polish
GIA VG
AGS G
EGL G
Symmetry
GIA G
AGS G
EGL G
Fluorescence
GIA No
AGS Ng
EGL Ft
No 13
Polish
GIA G
AGS G
EGL G
Symmetry
GIA G
AGS VG
EGL G
Fluorescence
GIA No
AGS Ng
EGL No
No 14
Polish
GIA EX
AGS EX
EGL VG
Symmetry
GIA EX
AGS EX
EGL VG
Fluorescence
GIA No
AGS Ng
EGL No
No 15
Polish
GIA VG
AGS VG
EGL G
Symmetry
GIA G
AGS EX
EGL VG
Fluorescence
GIA Ft
AGS Ng
EGL Ft
No 16
Polish
GIA VG
AGS VG
EGL G
Symmetry
GIA G
AGS G
EGL G
Fluorescence
GIA No
AGS Ng
EGL No
No 17
Polish
GIA VG
AGS VG
EGL G
Symmetry
GIA VG
AGS EX
EGL VG
Fluorescence
GIA No
AGS Ng
EGL No
Abbreviations
Polish and Symmetry
EX Excellent
ID Ideal
VG Very Good
G Good
Fluorescence
No None
Ng Negligible
Ft Faint

 

 

Appendix V. Clarity or Surface Feature Comments

  
 
No. Report Clarity or Surface Feature Comments
1 GIA 10980447 0 Inscription noted
AGS 0005083801 1 "GIA 10980447" has been inscribed on the girdle of this diamond
Additional clouds are not shown
EGL US 29659903D 0 -

2 GIA 12067698 0 Inscription noted
AGS 0005083802 1 "GIA 12067698" has been inscribed on the girdle of this diamond
Additional clouds are not shown
EGL US 29659904D 0 -

3 GIA 11600572 1 Pinpoints are not shown
AGS 0005083804 2 Pinpoints and surface grain line are not shown
EGL US 29659902D 0 -

4 GIA 11078850 1 Additional clouds are not shown
AGS 0005083803 1 Additional clouds are not shown
EGL US 29659901D 0 -

5 GIA 13359870 0 -
AGS 0004843410 0 -
EGL US 29809205D 0 -

6 GIA 13359793 0 -
AGS 0004416606 0 -
EGL US 29809204D 0 -

7 GIA 13359854 1 Additional clouds are not shown
AGS 0004843309 0 -
EGL US 29809206D 0 -

8 GIA 13359814 0 -
AGS 0003935809 0 -
EGL US 29809203D 0 -

9 GIA 13359863 0 -
AGS 0004819808 0 -
EGL US 29809202D 0 -

10 GIA 12911597 0 -
GIA 13359789 1 Clouds are not shown
EGL US 29809201D 0 -

11 GIA 12094476 1 Pinpoints are not shown
AGS 0005129801 0 -
EGL US 30248507D 0 -

12 GIA 12243841 2 Cloud is not shown
Surface graining is not shown
Crown angles are greater than 35 degrees
AGS 0005129802 2 Additional clouds and surface grain lines are not shown
EGL US 30248505D 0 -

13 GIA 12137092 0 -
AGS 0005129804 0 -
EGL US 30248501D 0 -

14 GIA 13146918 1 Additional clouds are not shown
AGS 0005129805 1 Additional clouds are not shown
EGL US 30248502D 0 -

15 GIA 12910179 3 Additional pinpoints, internal graining and surface graining are not shown
AGS 0005129806 1 Surface grain lines are not shown
EGL US 30248506D 0 -

16 GIA 11937949 0 Crown angles less than 30 degrees
AGS 0005129807 0 -
EGL US 30248503D 0 -

17 GIA 12243850 1 Clouds are not shown
AGS 0005129803 1 Clouds are not shown
EGL US 30248504D 0 -