Can a "not so well cut" diamond score well on HCA?

[dogchow]

Hi there,

I am currently shopping for a diamond for my girlfriend''s ering and am still learning. I came across this stone and am not necessarily interested in buying it, but I would appreciate your input. Here are the specs:

1.76 Round
I
SI1
Depth: 58.3%
Table: 57%
Crown Angle: 31.3
Pav Angle: 40.9
Symmetry: VG
Polish: VG
Very thin to Medium Girdle
Culet: V. Small .0.9

At first glance, this looks like a shallow stone- no very well cut. However, when I input the numbers into the HCA, it scored a 0.7 (Excellent in all categories). In the DIY cut adviser, the stone is a 2B. Why does this stone score so well on the HCA? Even though it''s cut on the shallow side, will be a good performer because of the good score on the HCA?

 

[Stephan]

This diamond could be gorgeous and very big for its carat weight, but the low crown angle with a very thin girdle is something dangerous...

 

[dogchow]

Stephan- thanks for your reply. How thin is too thin? The girdle is 0.7-1.4 (0.9) on the sarin. Is this a bad combo with the 31.3 crown? Does it mean it can easily be damaged?

 

[Stephan]

Date: 4/13/2005 12

5:54 PM
Author: dogchow
Stephan- thanks for your reply. How thin is too thin? The girdle is 0.7-1.4 (0.9) on the sarin. Is this a bad combo with the 31.3 crown? Does it mean it can easily be damaged?

Perhaps, but I''m not an expert.
Did you see the diamond?
It certainly looks breathtaking under halogene!

 

[valeria101]

Date: 4/13/2005 11:47:47 AM
Author:dogchow

In the DIY cut adviser, the stone is a 2B. Why does this stone score so well on the HCA?

The two rating systems take into accounting slightly different things...

The HCA score basically tells that those proportions have great chance to result in a very bright stone.

DIY takes that into account (although I cannot tell whether their grades agree to a tee with the HCA) and perhaps other things too. What and why... I can''t really tell: there is no official explanation I know of.

All in all, second what Stephan says.

Perhaps the thin girdle issue needs clarification and this stone remains to be seen just like any other. All these scores are just an approximation after all. The numbers sound promissing enough - not it''s time to see the goods

If you are planning use the service of an appraiser, the girdle issue would be sorted out the right (= professional) way. Otherwise, perhaps the seller could comment as sson as the diamond gets into their office. It seams reasonable that they would not want a not-so-great stone leave their shop. Of course, it is up to you to decide how much to trust the seller

Just my 0.2, of course.

 

[oldminer]

You may have one of the stones that is not cut to Tolkowsky, yet has excellent light behavior. A little shallow on the crown angle combined with a little steeper on the pavilion angle. These things can create great look and probably offer a good value as they are not yet considered "Ideal" in the traditional market. Do be careful with the very thin girdle. See how extensive it is.

 

[dogchow]

Thank you all for your advice. What problems are presented by diamonds with thin girdles? If it survives the setting, then would the thin girdle still be an issue?

 

[oldminer]

A thin girdle is not so much a setting problem as it is a problem of long term durability when the diamond is being worn on the hand. In a pendant or earrings it would be rare for a diamond to chip or fracture while being worn, but a ring is always at risk. Shallow crown angles combined with very thin girdle zones are a big culprit in the reason diamonds occasionally chip when worn. Pointed corners on princess cuts are notorious for chipping during the setting process. They are fragile, et mostly don''t break after the diamond is set.

 

[Garry H (Cut Nut)]

HCA is an aid to rejecting diamonds sight unseen. It is telling you to consider this stone - if you can focus your eyes well below 10 inches and examine it very close up you may not like it as a ring stone.
But if you are a little older you will find it quite possibly very beautiful.

Have an appraiser check the thin girdle out - it may be just 1 spot.