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What Specs to look for a Round and Princess Diamond

csriram45

Rough_Rock
Joined
Aug 28, 2006
Messages
43
Hello all,

As i try to learn more about the different specs for diamonds. I would appreciate if you can provide me some inputs on guide lines. Here is what I have so far for round. It seems like my wife may favor a Princess cut instead so I am a bit confused. Help me fill out the info for Princess please

Here is what I know for 1 carat diamond

Round

Cut: Ideal/Excellent
Color: Lowest perhaps I
Clarity: VS2. SI1 perhaps but i am being safe

Table - 53- 60 - Is this right range? Higher the table bigger the diamond appears correct?
Depth - lower than 63. Is this right range?
Crown angle < 35. Is this right range?
Pavilion angle < 41. Is this right range?
HCA - Excellent/Very Good
Polish - Excellent
Symmetry - Excellent


Princess:

Cut
Color
Clarity

Table
Depth
Crown angle
Pavilion angle
HCA - n/A
Polish - Excellent
Symmetry - Excellent
 

kenny

Super_Ideal_Rock
Premium
Joined
Apr 30, 2005
Messages
28,175
Round HCA under 2.0 and good Idealscope image.

Princess: Graded by AGS and got AGS's top cut grade of 0.
 

csriram45

Rough_Rock
Joined
Aug 28, 2006
Messages
43
For e.g. here is a round diamond that i am considering. Is this good? The depth seems slightly high and table not as good. Crown angle is also slightly higher. But Is it that off?

Shape and Style: Round Brilliant
Measurements: 6.64 - 6.68 x 4.18 mm
Cut Grade: AGS Ideal 0
Color Grade: AGS 2.0 (H)
Clarity Grade: AGS 4 (VS2)
Carat Weight 1.150
Fluorescence: Negligible
Comments:

Light Performance: 0
Polish: Ideal
Symmetry: Ideal
Table: 56.2%
Crown Angle: 35.5
Crown Height: 15.6%
Girdle: Faceted, 1.8% to 4.3%
Pavilion Angle: 40.8
Pavilion Depth: 43.1%
Star Length: 48%
Lower Girdle Length: 78%
Total Depth: 62.7%
Culet: Pointed
 

kenny

Super_Ideal_Rock
Premium
Joined
Apr 30, 2005
Messages
28,175
csriram45|1456109837|3993851 said:
For e.g. here is a round diamond that i am considering. Is this good? The depth seems slightly high and table not as good. Crown angle is also slightly higher. But Is it that off?

Shape and Style: Round Brilliant
Measurements: 6.64 - 6.68 x 4.18 mm
Cut Grade: AGS Ideal 0
Color Grade: AGS 2.0 (H)
Clarity Grade: AGS 4 (VS2)
Carat Weight 1.150
Fluorescence: Negligible
Comments:

Light Performance: 0
Polish: Ideal
Symmetry: Ideal
Table: 56.2%
Crown Angle: 35.5
Crown Height: 15.6%
Girdle: Faceted, 1.8% to 4.3%
Pavilion Angle: 40.8
Pavilion Depth: 43.1%
Star Length: 48%
Lower Girdle Length: 78%
Total Depth: 62.7%
Culet: Pointed
The HCA score is over 2.0 so I'd pass.
62.7% is too deep.

Round is the most plentiful diamond shape ... so be choosey.

screen_shot_2016-02-21_at_7.png
 

csriram45

Rough_Rock
Joined
Aug 28, 2006
Messages
43
How is HCA calculated? In the above spec? Looks like I need to more look at princess cut.
 

diamondseeker2006

Super_Ideal_Rock
Premium
Joined
Jan 11, 2006
Messages
55,630
These are measurements to help you stay in ideal cut territory with a GIA excellent cut stone. I agree that I would not buy a stone over 62.3 in depth as it usually results in the diameter being smaller than it should for the weight.

crown angle: 34-35.0

table: 54-58

depth: 60-62.3

pavilion angle: 40.6-40.9 (sometimes 41.0 if crown angle is close to 34)
 

diamondseeker2006

Super_Ideal_Rock
Premium
Joined
Jan 11, 2006
Messages
55,630
We would want to see you get what she loves most, but I will tell you that rounds are timeless and I believe princess cuts will become dated like marquise, etc. It is far easier to choose an excellent round than a princess cut. The best option for a princess cut is to go on a site like Whiteflash and choose one of their ACA ideal cut princess stones. They have been evaluated for light return and cut to be superior stones.
 

kenny

Super_Ideal_Rock
Premium
Joined
Apr 30, 2005
Messages
28,175
csriram45|1456113009|3993864 said:
How is HCA calculated? In the above spec?
Click on this link: https://www.pricescope.com/tools/hca
Here is a screen capture of part of what you will see.



Enter four numbers from the lab report into the HCA screen.
Press GO and the HCA does its magic math and spits out a score.

If you're asking what exactly the math formula is you'd have to ask Garry Holloway the owner/inventor of the HCA, or Holloway Cut Advisor.

I suspect the math is proprietary, though.

screen_shot_2016-02-21_at_10.png
 

csriram45

Rough_Rock
Joined
Aug 28, 2006
Messages
43
I talked to her and she has agreed to stick to round. She does want a cushion cut setting with a round center. Now the specs above seem quiet specific. Will try to look for diamonds under that spec.
 

diamondseeker2006

Super_Ideal_Rock
Premium
Joined
Jan 11, 2006
Messages
55,630
csriram45|1456243446|3994431 said:
I talked to her and she has agreed to stick to round. She does want a cushion cut setting with a round center. Now the specs above seem quiet specific. Will try to look for diamonds under that spec.
Awesome! Ritani makes a nice quality cushion halo if you'd like to look at Whiteflash's in-stock diamonds. All of their ACAs and Expert Selection stones should fall in the cut parameters I gave you above.
 

csriram45

Rough_Rock
Joined
Aug 28, 2006
Messages
43
diamondseeker2006|1456244737|3994444 said:
csriram45|1456243446|3994431 said:
I talked to her and she has agreed to stick to round. She does want a cushion cut setting with a round center. Now the specs above seem quiet specific. Will try to look for diamonds under that spec.
Awesome! Ritani makes a nice quality cushion halo if you'd like to look at Whiteflash's in-stock diamonds. All of their ACAs and Expert Selection stones should fall in the cut parameters I gave you above.
Nice. looking around for diamond based on spec you gave. Will look at WF as well. Any links on the setting that you can suggest?
 

csriram45

Rough_Rock
Joined
Aug 28, 2006
Messages
43
how does this look

Cut:Excellent
Color:I
Clarity:VS1
Depth:62.30
Table:57.00
Polish:Excellent
Symmetry:Excellent
Girdle:M-STK
Culet:None
Fluorescence:None
Ratio:0.00
Measurements:6.61x6.65x4.13

Table - 57%
Depth - 62.3
Crown - 35
Pavilion - 40.8

HCA came as 1.7. Seems like a good one. Have requested Idealscope and ASET images to compare as well. Anything that is of concern?
Also what is a preferred range of HCA? Closer to 1 better?
 

csriram45

Rough_Rock
Joined
Aug 28, 2006
Messages
43
csriram45|1456299541|3994830 said:
how does this look

Cut:Excellent
Color:I
Clarity:VS1
Depth:62.30
Table:57.00
Polish:Excellent
Symmetry:Excellent
Girdle:M-STK
Culet:None
Fluorescence:None
Ratio:0.00
Measurements:6.61x6.65x4.13

Table - 57%
Depth - 62.3
Crown - 35
Pavilion - 40.8

HCA came as 1.7. Seems like a good one. Have requested Idealscope and ASET images to compare as well. Anything that is of concern?
Also what is a preferred range of HCA? Closer to 1 better?

Got the idealscope and ASET images too. On road will upload when I get a chance to be in front of computer!
 

flyingpig

Ideal_Rock
Premium
Joined
Nov 7, 2015
Messages
2,175
Is the 1st set of images 1.13 I VS1??
The reason why I ask is that there are visible black dots right in the cneter in all ASET, IS and diamond images. But these inclusions are not indicated in I VS1's GIA report.

The 2nd set of images.. I think those are taken slightly tilted to right...
 

csriram45

Rough_Rock
Joined
Aug 28, 2006
Messages
43
The 1st set if for the 1.08 and the 2nd for 1.13. I will ask for the images again getting them right. Thank you for the catch. Any initial thoughts with the images we have currently?

Is 1.08 good? I still like the 1.13 as it has good spread and is less expensive of the 2 but want to make sure its good
 

flyingpig

Ideal_Rock
Premium
Joined
Nov 7, 2015
Messages
2,175
1.13 has better proportions. I like it, too.
It is unfortunate that the light performance images may have taken slightly tilted, which may cause those slight light leakage under the table at 1, 2, 3 o'clock positions.
Regardless, I think it is still a beautiful stone.
 
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