HCA 5.6

[noob529]

This stone looked great in the store but gets a horrible hca. here are the stats

depth 62.5
table 58
crown 35
pavilion 41.5
gia cert
ex- cut
vg- symetry
ex- polish

Should i buy this?

 

[neatfreak]

NO. You want a HCA under 2.5, under 2 is optimal.

Wait, this is a round correct?

Did you see it in different light conditions? Have you seen many stones, or just a few? Were you able to compare it to some nicer and not as nice diamonds side by side? All of these might have an impact on why you thought it looked nice, but isn't.

ETA: Ask for a Sarin and Idealscope too. There might be major light leakage somewhere.

 

[belle]

it''s up to you whether or not you want to buy. do you feel like you made an adequate amount of comparisons to be able to make an informed decision?

 

[noob529]

yes it is a round stone...I dont understand how its such a bad HCA when the GIA rates it an Excellent Cut.

I have looked at several stones, this one seemed to look the best in person. It sparkled like no other one. How can the HCA be so bad.

 

[Ellen]

Date: 5/10/2007 2:47:00 PM
Author: belle
it''s up to you whether or not you want to buy. do you feel like you made an adequate amount of comparisons to be able to make an informed decision?

Ditto. If you compared it to, say, some AGS000''s and liked it better, then it may be for you.

If you haven''t done that, it might not be a bad idea.

 

[neatfreak]

Date: 5/10/2007 2:52:36 PM
Author: noob529
yes it is a round stone...I dont understand how its such a bad HCA when the GIA rates it an Excellent Cut.


I have looked at several stones, this one seemed to look the best in person. It sparkled like no other one. How can the HCA be so bad.

This might be a silly question, but you input the numbers correctly and did not round them when you put them into the HCA right? Small discrepancies can make a big difference in scores...

 

[belle]

there are some ''odd'' angle combinations that don''t do well on hca. unfortunately, getting a gia ''excellent'' cut does not in itself mean that you are getting the best cut possible either. it may have been better than the others that you looked at but what quality were they?
as ellen said, perhaps you should have a look at some ags0''s for compairson. you may still prefer this diamond but at least you will know you made an informed decision.

best of luck!

 

[noob529]

yea i put them in right without rounding. The thing that i have read on here is that the score can be skewed from the pavilion angle being >41. is this the case?

 

[Ellen]

It is true that a PA of 41 and greater really knocks the score down. I have a 41 PA, but coupled with a 34 CA.

Your stone has a high CA AND and very deep PA. Chances are, it''s rather leaky. That''s why I suggest looking at some real ideals to make sure you''re doing a good comparison. If you do that, and you still like it, it''s the one.

And make sure if you compare to get outside or at least by a window, jewelers lights make everything look good.

 

[kcoursolle]

Slightly too deep, table is slightly large, and yes crown/pavillion angles are less than optimal...You can find a much better cut stone out there.

 

[noob529]

They did a gemex on it and it was considered very high for the all the criteria...does that mean anything?

 

[belle]

Date: 5/10/2007 3:07:22 PM
Author: kcoursolle

Slightly too deep

lol....is that like 'a little pregnant'?

btw noob, i wouldn't consider 62.5 'too deep'

 

[Ellen]

Date: 5/10/2007 3:10:21 PM
Author: noob529
They did a gemex on it and it was considered very high for the all the criteria...does that mean anything?

No. Get an IS image, that would.

 

[shel]

Date: 5/10/2007 3:10:21 PM
Author: noob529
They did a gemex on it and it was considered very high for the all the criteria...does that mean anything?

Gemex is reassuring. Now compare it to AGS000 stones and trust your eyes.

 

[kcoursolle]

Date: 5/10/2007 3:11:58 PM
Author: belle

Date: 5/10/2007 3:07:22 PM
Author: kcoursolle

Slightly too deep

lol....is that like ''a little pregnant''?

btw noob, i wouldn''t consider 62.5 ''too deep''

In my opinion, it''s slightly too deep for *my* preferences, but stones in the 62-63 range can have very nice performance. I should definitely be more specific, thanks belle!

 

[JohnQuixote]

Date: 5/10/2007 2:43:23 PM
Author:noob529

This stone looked great in the store but gets a horrible hca. here are the stats

...Should i buy this?

We can''t possibly tell you. If you provide carat weight, spread in mm, girdle thickness and girdle min-max a bit more could be determined.Otherwise we can only guess, as the HCA did. You’re in the best position to make the call, since you have seen the diamond...

Date: 5/10/2007 2:45:36 PM
Author: neatfreak

Did you see it in different light conditions? Have you seen many stones, or just a few? Were you able to compare it to some nicer and not as nice diamonds side by side? All of these might have an impact on why you thought it looked nice, but isn''t.

This is where I''d start. Beyond that an ideal-scope or ASET image, plus the missing data, will help us help you.

 

[noob529]

How does the Gemex compare to a "theoretical" test like the HCA

 

[JohnQuixote]

Date: 5/10/2007 3:50:29 PM
Author: kcoursolle

Date: 5/10/2007 3:11:58 PM
Author: belle

Date: 5/10/2007 3:07:22 PM
Author: kcoursolle

Slightly too deep

lol....is that like 'a little pregnant'?

btw noob, i wouldn't consider 62.5 'too deep'

In my opinion, it's slightly too deep for *my* preferences, but stones in the 62-63 range can have very nice performance. I should definitely be more specific, thanks belle!

Good points.Depths up to 62.9 may earn the top cut grade from both major labs so 62.5 is ok.KC, also remember that if the table was smaller this diamond would be even deeper.

Diamonds with girdles best suited for tension settings often fall into the 62.X range, depending on other parameters.

Noob, some of the reactions you're reading are because the C/P angles are deeper than what we’re used to seeing on PS (41.5 PA, especially, is outside of a strict near-Tolkowsky range).However, to be ‘slightly steep’ in trade terms the PA would need to be around 41.8 degrees. Moderately steep is around 42.4.

 

[noob529]

here are the dimensions of the stone. 7.29-7.24-4.54 and girdle is stk the ct weight is 1.48cts

 

[Regular Guy]

Date: 5/10/2007 3:56:20 PM
Author: noob529
How does the Gemex compare to a ''theoretical'' test like the HCA

You could consider as basic, the first part of the Pricescope Tutorial on "cut".....

The HCA is in group #1, Proportions and Predictive
Gemex is in group #2, with direct measurement
AGS is represented in group #3, which I think, the sentiment is, is better than either #1 or #2 in the same way that calculus is an improvement in doing math, fitting the specific diamond closer and closer under the approximation of what could otherwise be the prediction of the curve.

Anyway, I say, you need multiple tests, unless you''re better than most experts. There''s lots of diamonds. Don''t fixate on one. Get one that passes more than one test, like Gemex, alone.

Regards,

 

[Cehrabehra]

Date: 5/10/2007 3:11:58 PM
Author: belle

Date: 5/10/2007 3:07:22 PM
Author: kcoursolle

Slightly too deep

lol....is that like ''a little pregnant''?

btw noob, i wouldn''t consider 62.5 ''too deep''

the stats reminded me a bit of an old cut stone - the stone very well may be VERY firey but just not as bright as some others prefer. I wonder what the lgfs are...

BTW the HCA isn''t everything, it''s just a tool - even garry will tell you that

 

[JohnQuixote]

Date: 5/10/2007 4:58:43 PM
Author: Cehrabehra

the stats reminded me a bit of an old cut stone - the stone very well may be VERY firey but just not as bright as some others prefer. I wonder what the lgfs are...

Or it may be the opposite. Using the additional stats noob provided the crown height is only about 14.5% (with a STK girdle of appx 1.5%). Along with the 59% table, this would lend itself to more brightness in the balance. The PA is deep enough that there may be some leakage. That's why an IS would help.

When cutting these makes the lower halves will usually be reported as 75% or 80%, but with GIA's rounding that accounts for most rounds we hear about in these parts.

 

[strmrdr]

personally Id pass on that combo.

 

[JohnQuixote]

Should i buy this?

We've established that it's a 1.48 at the border of GIA EX and VG in cut. Without more info this is about as far as we can go.

If highest cut pedigree is not your top priority (it's a D, for example, and that is what's most important to you) it may be priced well, being just shy of that commercially important 1.50 ct mark. Only you know its color, clarity and price - and only you know your preferences and budget.

 

[Garry H (Cut Nut)]

It has a 4% smaller spread than in an ideal world.
The edges will not return as much ligth - so it will look like a 1.30
when it is dirty the edges will be even deader and there will then be a ring of death just inside the table.


But if you like it then buy it

 

[Ellen]

Gary, I hate it when you beat around the bush (and you do it SO often), be honest for petes sake.

 

[JohnQuixote]

Sorry noob. I''ve tried to be PC.

Between "best cut ever" and "no way no how" there is a gray area. This one''s in the gray, in case you hadn''t noticed.

 

[Cehrabehra]

Date: 5/10/2007 5:20:08 PM
Author: JohnQuixote

Date: 5/10/2007 4:58:43 PM
Author: Cehrabehra

the stats reminded me a bit of an old cut stone - the stone very well may be VERY firey but just not as bright as some others prefer. I wonder what the lgfs are...

Or it may be the opposite. Using the additional stats noob provided the crown height is only about 14.5% (with a STK girdle of appx 1.5%). Along with the 59% table, this would lend itself to more brightness in the balance. The PA is deep enough that there may be some leakage. That''s why an IS would help.

When cutting these makes the lower halves will usually be reported as 75% or 80%, but with GIA''s rounding that accounts for most rounds we hear about in these parts.

that''s true john... my earrings are cut similarly to the above stone and they are VERY bright but have almost no fire

 

[Cehrabehra]

Date: 5/10/2007 8:08:43 PM
Author: JohnQuixote
Sorry noob. I''ve tried to be PC.

Between ''best cut ever'' and ''no way no how'' there is a gray area. This one''s in the gray, in case you hadn''t noticed.

And the bargain that can sometimes be had in that area provides enough beauty for some women to make them happy and keep them smiling for a lifetime But if you''re paying the same price for a stone in the grey area as you could for an ideal.... its a simple choice to me!