shape
carat
color
clarity

please give me your opinion on these 3 rocks

diamondseeker2006

Super_Ideal_Rock
Premium
Joined
Jan 11, 2006
Messages
58,547
The only one of these I'd consider is the second one, but I'd still need to see a magnified picture of the stone and preferably a light return image such as Idealscope or ASET.

These are measurements to help you stay in ideal cut territory with a GIA excellent cut stone.

table: 54-58

depth: 60-62.3

crown angle: 34-35.0

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


Also, there is a screening tool for GIA ex cut stones:

https://www.pricescope.com/tools/hca

You want to see Excellent on light return, fire, and scintillation, and very good on spread. An overall score of 2.0 or lower means a diamond is worth exploring further (but a 1.0 isn’t necessarily better than 1.9).
 

JacquelineT

Rough_Rock
Joined
Mar 13, 2016
Messages
18
Hi diamondseeker,
Thank you for taking your time to help me. I greatly appreciate it. I'm a liitle confuse with your decision because the Hca score for 1.8 carat is 1.9 with excellent in fire and everything else is very good. And hca score for 1.9 carat is 2.4 with very good in all categories. So why is it that you would choose the 1.9 carat over the 1.8 . And which one do you think have the best value?
 

flyingpig

Ideal_Rock
Premium
Joined
Nov 7, 2015
Messages
2,978
HCA has its own set of limitations. One is that its inability to recognize poorly cut diamond with extreme pav/crown angles. It favours stones with steep/shallow, shallow/steep angles.
Try and see what you get for 62.4 depth, 57 table, 38 crown, and 40 pavillion
Result? 1.1 with 3 excellent in three categories. But in fact.. such diamond would be terrible. I am not too sure if such thing even exists.

#1's 40.6/36.0 is a shallow/STEEP combo. It can work and it does sometimes. Although, not ideal, I would consider this combo as long as the IS confirms no significant light leakage, and price is adjusted accordingly.
http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3500063.htm (example of shallow/STEEP combo. Still beautiful. But not the best; white patches under the table=light leakage=less bright)
#2 is 41/35 (steep/steep) combo can work, and potentially better than 40.6/36.0, depending on the actual angle. 41/35 falls within the orthodox ideal proportions diamondseeker listed, although 41/35 don't compliment each other well. You want more like 40.6/35 or 41/34 (33.5) or 40.8/34.5)
GIA report rounds crown angle to the nearest 0.5, and pav angle to the nearest 0.2. So if 41/35 really happens to be 40.9/34.7, it is very promising. If it is more like 41.1/35.2, it is less promising.

But there is no way to find this out without Sarin report and/or Idealscope/ASET image.

Neither stone is thrilling..

Can't say about #3, since it is a fancy shaped diamond, and not enough information is available on the report. Need the actual image and ASET image.

That's my opinion.
 
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