diamond comparision

[thomasw]

I have lost the following diamond:

oval brilliant
7.45x5.54x3.26
0.9 carats
depth: 58.8%
table 56%
girdle: medium to slightly thick, faceted
cutlet: none
polish: good
symmetry: good
color grade: D
fluorescence: none
GIA certificate

I have been offerred the following:
round brilliant
weight: 1 ct
clarity: vvs2
flurescence: nil
colour grade: exceptional whilte + (D)
6.4x 6.45 x 3.96
proportions: very good
girdle: medium 3.5 % faceted
cutlet: pointed
table width 59%
cr height: 14.5%
pav.depth 44%
finish grade: very good
this has been certified by HRD Certificates Department (which is BELTEST accredited)
I have been asked to pay an extra £1,575.

Please could you give me any comments you have on the new diamond and whether you think this is a good deal.

Your help is very much appreciated!!

 

[Colored Gemstone Nut]

----------------
On 4/23/2003 6:24:46 AM thomasw wrote:
I have lost the following diamond:

oval brilliant
7.45x5.54x3.26
0.9 carats
depth: 58.8%
table 56%
girdle: medium to slightly thick, faceted
cutlet: none
polish: good
symmetry: good
color grade: D
fluorescence: none
GIA certificate

I have been offerred the following:
round brilliant
weight: 1 ct
clarity: vvs2
flurescence: nil
colour grade: exceptional whilte + (D)
6.4x 6.45 x 3.96
proportions: very good
girdle: medium 3.5 % faceted
cutlet: pointed
table width 59%
cr height: 14.5%
pav.depth 44%
finish grade: very good
this has been certified by HRD Certificates Department (which is BELTEST accredited)
I have been asked to pay an extra £1,575.

Please could you give me any comments you have on the new diamond and whether you think this is a good deal.

Your help is very much appreciated!!

----------------

Thomas W: A couple things to keep in mind when pricing and comparing stones-

(1) There is a premium on round brilliant stones versus oval cut stones. Round Brilliant cuts are more expensive than the ovals. Round brilliants generate more light return.

(2) The oval cut stone you are looking at is under a carat and the round brilliant hits the 1 carat mark. The 1 carat mark reached carries a premium because of it's weight. Sometimes the weight is referred to as hitting the magic number. Being that there is a premium placed on stones tat fall in that category in this case "the one carat mark".

To find out whether its a "good deal" or not list the total price for each stone you have listed.....

-Josh Rioux
Sitka, Alaska

 

[thomasw]

the oval was insured at £8,175 and I;m being asked to pay £9,750 for the brilliant

 

[Richard Sherwood]

Hi Thomas. The price premium of the 1 carat round over the 0.90 oval should be in the neighborhood of 18%, give or take.

The difference in the two prices you listed is 19%, so the premium being asked is a fair one.

The cut is technically in the "very good" category (an AGS 1, or AGS 2A). I ran the stats through the DiamCalc Light Return Analysis and came up with the following POSSIBLE profile, along with a POSSIBLE IdealScope simulated image:

Light Return (mono)…...: 0.90 Very Good to Good
Light Return (stereo)…..: 0.93 Very Good to Good
(Non) Leakage (mono)..: 0.54 Poor (I feel "fair" is more appropriate wording)
(Non) Leakage (stereo).: 0.60 Poor (" " ")
Contrast............................: 0.96 Very Good
(Non) FishEye Effect…...: 1.00 Very Good

-----------
IdealScope- In general, the darker pink areas indicate areas of greater light return, with the lighter pink areas indicating areas of lesser light return. The black areas indicate areas of greater contrast, with the gray areas indicating areas of lesser contrast. The white areas indicate areas of light leakage. A good explanation of the IdealScope image along with examples can be found at https://www.pricescope.com/idealscope_indx.asp

Disclaimer- The facet arrangement and symmetry of the image will probably vary from your actual diamond, which may affect the light performance indicated. The computer generates an image with “perfect” symmetry, which is rare. Also, the star/lower girdle facet lengths may be different from your diamond. The computer simulation is reproduced best when the actual diamond is being viewed and the image "tweaked" to the appearance of the diamond, or Sarin info is downloaded directly into the program. However, this "blind" reproduction should be helpful in considering the major light performance aspects..
-----------

 

[Richard Sherwood]

1.00 RBC- Thomas

 

[Richard Sherwood]

photoreal simulated image

 

[Richard Sherwood]

The white area you're seeing inside the table on the simulated IdealScope image is what's dragging the (non)leakage specs down. This leakage will create a moderately darker effect inside the table than a more "ideally" cut stone.

The majority of diamonds sold have characteristics like this, so it's not out of the "norm". I just point it out to you as an appraiser, so you'll have complete knowledge of the stone's performance.

Above I attached a "photoreal" simulated image which will give you an idea of where the darkness would be, so you can look for it when you visually inspect the stone. If it's not as bad as the image shown, or if you like the stone regardless, the extra percentage being asked from you is in line.

 

[Lanee]

Mr. Sherwood, Can I call you Rich or Ric? I love the post with the pics from DiamCalc. Can you do that with any shape stone?

 

[thomasw]

Rich

I am going to see the diamond tomorrow and shall look out for the dark areas you suggested might be there. My oval also wasn't perfect so I think there is a limit to how much I can ask for from the insurer for a replacement.

I am very grateful for all your help.

TW

 

[thomasw]

Rich

I have been to see my diamond which looks beautiful to me. Thanks again for all your help. I think I have been very lucky with your (and others) help and the jeweller.

TW

 

[Colored Gemstone Nut]

----------------
On 4/26/2003 11:52:13 AM thomasw wrote:
Rich

I have been to see my diamond which looks beautiful to me. Thanks again for all your help. I think I have been very lucky with your (and others) help and the jeweller.

TW----------------

Hey ThomasW-Post pic's of the whole shabang when your done....Congrats-

Josh Rioux
Sitka, Alaska

 

[Richard Sherwood]

Hi Thomas, glad it all worked out.

Lanee, call me Rich. Although the DiamCalc software handles all the standard cuts and a few non-traditional cuts, I usually don't post profiles on non-round stones. The nuances of fancy cuts are so prolific that they often create completely different IdealScope images and Light Return Analysis' than the subject stone.

As RockDoc so often states, fancy cuts have to be seen to be properly analyzed.

Sometimes I'll post simple profiles to illustrate length-to-width or some such thing, but don't usually go more in depth than that.