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ť GIA Very Good = HCA 0.8 ?

GIA Very Good = HCA 0.8 ?

P: 4/29/2009 3:35:46 PM
thaihunt Rough Rock Total Posts: 31 Last Post: 5/14/2009 Member Since: 4/23/2009	Ran across this diamond, GIA Very Good, and plugged the numbers into HCA. Came out with Excellents across the board with h a 0.8 score. Thoughts on the diamond and how to explain the grading of VG with an Excellent HCA score? 1.50 Table: 58% Depth: 60.1% Crown: 33% Pavilion: 40.8% 7.417.434.46 Girdle: Med to Slightly Thick
Posted: 4/29/2009 3:35:46 PM

There are 20 replies to this message. There are 20 replies on this page.

P: 4/29/2009 3:39:38 PM
QueenMum Ideal Rock Total Posts: 1,971 Last Post: 10/28/2009 Member Since: 2/13/2003	GIA, like most of the diamond cutters, prefers deep diamonds. However, is there something written under 'Comments' in your certificate? What are star and lower girdle length? Stephan
Posted: 4/29/2009 3:39:38 PM

P: 4/29/2009 3:41:01 PM
jet2ks Ideal Rock Total Posts: 1,581 Last Post: 11/23/2009 Member Since: 2/4/2009	Do you have the rest of the info on this diamond? Polish and symmetry would be the first place I would look. Any of my opinions are worth exactly what you paid for them. "The U. S. Constitution doesn't guarantee happiness, only the pursuit of it. You have to catch up with it yourself." Benjamin Franklin
Posted: 4/29/2009 3:41:01 PM

P: 4/29/2009 3:43:15 PM
thaihunt Rough Rock Total Posts: 31 Last Post: 5/14/2009 Member Since: 4/23/2009	Comments say there is some surface graining and additional pinpoints. Not sure what you mean by star and lower girdle length, but I see the following measurements: From cullet to girdle: 43%. From girdle to table: 13.5% Are those what you're referring to?
Posted: 4/29/2009 3:43:15 PM

P: 4/29/2009 3:44:04 PM
thaihunt Rough Rock Total Posts: 31 Last Post: 5/14/2009 Member Since: 4/23/2009	Polish and Sym are both excellent.
Posted: 4/29/2009 3:44:04 PM

P: 4/29/2009 3:58:14 PM
QueenMum Ideal Rock Total Posts: 1,971 Last Post: 10/28/2009 Member Since: 2/13/2003	Date: 4/29/2009 3:43:15 PM Author: thaihunt Not sure what you mean by star and lower girdle length, but I see the following measurements: From cullet to girdle: 43%. From girdle to table: 13.5% Are those what you're referring to? No... Stephan
Posted: 4/29/2009 3:58:14 PM

P: 4/29/2009 4:00:33 PM
thaihunt Rough Rock Total Posts: 31 Last Post: 5/14/2009 Member Since: 4/23/2009	Let me try again then :) I see two more measurements - can't tell exactly what they're referring to, but one is on the top of the diamond, and the other is on the bottom. They are 55% (top) and 75% (bottom). Hopefully those are what you need.
Posted: 4/29/2009 4:00:33 PM

P: 4/29/2009 4:07:41 PM
QueenMum Ideal Rock Total Posts: 1,971 Last Post: 10/28/2009 Member Since: 2/13/2003	You've got it. It sounds OK, even if I'm not a surface graining fan. Could you have an IdealScope picture? Stephan
Posted: 4/29/2009 4:07:41 PM

P: 4/29/2009 4:27:24 PM
phoenixgirl Ideal Rock Total Posts: 2,496 Last Post: 11/23/2009 Member Since: 3/20/2003	I trust the HCA more than the GIA when it comes to cut grading. The GIA probably doesn't like the crown angle or table. But all the angles on your stone are working together in the right ways. It's the way the angles interact, not their numbers alone, that determine cut quality. Better to find a GIA VG that scores high on the HCA than a GIA excellent that doesn't. If you search you can find some shockingly poor GIA excellents!
Posted: 4/29/2009 4:27:24 PM

P: 4/29/2009 4:31:06 PM
thaihunt Rough Rock Total Posts: 31 Last Post: 5/14/2009 Member Since: 4/23/2009	Thanks for the responses. I requested a ideal-scope image and will certainly post it here when it arrives. Cut and light performance are my main priorities, so I just wanted to make sure that I shouldn't be turned off because of the VG rating.
Posted: 4/29/2009 4:31:06 PM

P: 4/29/2009 4:33:06 PM
QueenMum Ideal Rock Total Posts: 1,971 Last Post: 10/28/2009 Member Since: 2/13/2003	Date: 4/29/2009 4:27:24 PM Author: phoenixgirl Better to find a GIA VG that scores high on the HCA than a GIA excellent that doesn't. If you search you can find some shockingly poor GIA excellents! That's so true! Stephan
Posted: 4/29/2009 4:33:06 PM

P: 4/29/2009 4:37:40 PM
Ellen Ideal Rock Total Posts: 22,894 Last Post: 11/6/2009 Member Since: 1/13/2006	Date: 4/29/2009 3:39:38 PM Author: QueenMum GIA, like most of the diamond cutters, prefers deep diamonds. However, is there something written under 'Comments' in your certificate? What are star and lower girdle length? Are you thinking this diamond is deep? At 60.1, that's not deep, nor is the PA. To the OP, I'd rather see the crown angle at 34 plus. This stone, overall, is leaning just slightly towards the shallow-er side. It "may" lack a bit of scintillation/possibly appear slightly glassy/possibly lack a bit of fire. Numbers are rounded, so in actuality, might be a bit better, or might not. Plus, look where the x is (on HCA), it's outside the boxes. You'd prefer it in the overlap area, or closer to. Don't just look at the numerical score. ~~~~~~~~~~~~~~~~ "It is also important for the State to inculcate in its subjects an aversion to any 'conspiracy theory of history' for a search for 'conspiracies' means a search for motives and an attribution of responsibility for historical misdeeds." -Murray N. Rothbard, in The Anatomy of the State John Swinton [1829-1901] Chief Editorial Writer of the New York Times (Considered "the Dean of his Profession" by his peers), when asked to toast an 'Independent Press' in a gathering at the National Press Club, circa 1880 "There is no such thing in America as an independent press unless it is in the country towns. You know it, and I know it. There is not one of you who dare express an honest opinion. If you express it you know beforehand that it would never appear in print. I am paid... for keeping my honest opinions out of the paper I am connected with. Others of you are paid similar salaries for doing similar things.... The business of the New York journalist is to distort the truth, to lie outright, to pervert, to vilify, to fawn at the feet of Mammon, and sell his country and race for his daily bread, or for what is about the same thing, his salary. You know this, and I know it and what foolery to be toasting an 'independent press.' We are tools, and the vassals of rich men behind the scenes. We are jumping-jacks. They pull the strings and we dance. Our time, our talents, our lives, our possibilities, all are the property of other men. We are intellectual prostitutes."
Posted: 4/29/2009 4:37:40 PM

P: 4/29/2009 4:44:17 PM
QueenMum Ideal Rock Total Posts: 1,971 Last Post: 10/28/2009 Member Since: 2/13/2003	No, this diamond is not deep, that's why it only scores VG for the GIA. Stephan
Posted: 4/29/2009 4:44:17 PM

P: 4/29/2009 4:45:18 PM
Stone-cold11 Ideal Rock Total Posts: 6,893 Last Post: 11/23/2009 Member Since: 9/9/2008	Date: 4/29/2009 4:37:40 PM Author: Ellen Date: 4/29/2009 3:39:38 PM Author: QueenMum GIA, like most of the diamond cutters, prefers deep diamonds. However, is there something written under 'Comments' in your certificate? What are star and lower girdle length? Are you thinking this diamond is deep? At 60.1, that's not deep, nor is the PA. I don't think QM meant it that way. Just that GIA's Ex is in the higher PA range, not the lower PA range for the respective CA. A lower PA will less likely to get a Ex in cut but still be <2 on the HCA.
Posted: 4/29/2009 4:45:18 PM

P: 4/29/2009 5:03:31 PM
QueenMum Ideal Rock Total Posts: 1,971 Last Post: 10/28/2009 Member Since: 2/13/2003	Date: 4/29/2009 4:37:40 PM Author: Ellen It 'may' lack a bit of scintillation/possibly appear slightly glassy/possibly lack a bit of fire. I don't think so. Perhaps a little more obstruction than in a steep/deep. A longer lower girdle (around 80%) would be better than +/-75%. If I'm wrong, Karl will correct me. So let us take a look at the IdealScope! Stephan
Posted: 4/29/2009 5:03:31 PM

P: 4/29/2009 5:07:27 PM
Ellen Ideal Rock Total Posts: 22,894 Last Post: 11/6/2009 Member Since: 1/13/2006	Ok, I understand what you were saying now! However, I wouldn't necessarily say that GIA likes them deep, although many EX are deep. More that they have to balance each other out. If you leave the PA alone, and make the CA 33.5, you're back in EX territory (with the x). Make it 34, and you're in the overlap. You can look at it either way, bring the CA up higher, or make the PA deeper. ~~~~~~~~~~~~~~~~ "It is also important for the State to inculcate in its subjects an aversion to any 'conspiracy theory of history' for a search for 'conspiracies' means a search for motives and an attribution of responsibility for historical misdeeds." -Murray N. Rothbard, in The Anatomy of the State John Swinton [1829-1901] Chief Editorial Writer of the New York Times (Considered "the Dean of his Profession" by his peers), when asked to toast an 'Independent Press' in a gathering at the National Press Club, circa 1880 "There is no such thing in America as an independent press unless it is in the country towns. You know it, and I know it. There is not one of you who dare express an honest opinion. If you express it you know beforehand that it would never appear in print. I am paid... for keeping my honest opinions out of the paper I am connected with. Others of you are paid similar salaries for doing similar things.... The business of the New York journalist is to distort the truth, to lie outright, to pervert, to vilify, to fawn at the feet of Mammon, and sell his country and race for his daily bread, or for what is about the same thing, his salary. You know this, and I know it and what foolery to be toasting an 'independent press.' We are tools, and the vassals of rich men behind the scenes. We are jumping-jacks. They pull the strings and we dance. Our time, our talents, our lives, our possibilities, all are the property of other men. We are intellectual prostitutes."
Posted: 4/29/2009 5:07:27 PM

P: 4/29/2009 5:08:00 PM
QueenMum Ideal Rock Total Posts: 1,971 Last Post: 10/28/2009 Member Since: 2/13/2003	Date: 4/29/2009 4:37:40 PM Author: Ellen It 'may' lack a bit of scintillation/possibly appear slightly glassy/possibly lack a bit of fire. Fire is difficult to discuss as there are differences between diffuse or spot lighting. To my eyes, slightly shallow diamonds have better and more intense fire under spot lighting than deep ones. Deep diamonds have better fire under diffuse lighting than shallow ones. But that is just what my only eye can see, the other one is blind. But what is even more constant to my eye is the lack of scintillation of steep/deep diamonds. Stephan
Posted: 4/29/2009 5:08:00 PM

P: 4/29/2009 5:09:16 PM
Ellen Ideal Rock Total Posts: 22,894 Last Post: 11/6/2009 Member Since: 1/13/2006	Date: 4/29/2009 5:03:31 PM Author: QueenMum Date: 4/29/2009 4:37:40 PM Author: Ellen It 'may' lack a bit of scintillation/possibly appear slightly glassy/possibly lack a bit of fire. I don't think so. Perhaps a little more obstruction than in a steep/deep. A longer lower girdle (around 80%) would be better than +/-75%. If I'm wrong, Karl will correct me. So let us take a look at the IdealScope! An IS won't necessarily show what I've noted. ~~~~~~~~~~~~~~~~ "It is also important for the State to inculcate in its subjects an aversion to any 'conspiracy theory of history' for a search for 'conspiracies' means a search for motives and an attribution of responsibility for historical misdeeds." -Murray N. Rothbard, in The Anatomy of the State John Swinton [1829-1901] Chief Editorial Writer of the New York Times (Considered "the Dean of his Profession" by his peers), when asked to toast an 'Independent Press' in a gathering at the National Press Club, circa 1880 "There is no such thing in America as an independent press unless it is in the country towns. You know it, and I know it. There is not one of you who dare express an honest opinion. If you express it you know beforehand that it would never appear in print. I am paid... for keeping my honest opinions out of the paper I am connected with. Others of you are paid similar salaries for doing similar things.... The business of the New York journalist is to distort the truth, to lie outright, to pervert, to vilify, to fawn at the feet of Mammon, and sell his country and race for his daily bread, or for what is about the same thing, his salary. You know this, and I know it and what foolery to be toasting an 'independent press.' We are tools, and the vassals of rich men behind the scenes. We are jumping-jacks. They pull the strings and we dance. Our time, our talents, our lives, our possibilities, all are the property of other men. We are intellectual prostitutes."
Posted: 4/29/2009 5:09:16 PM

P: 4/29/2009 5:18:43 PM
QueenMum Ideal Rock Total Posts: 1,971 Last Post: 10/28/2009 Member Since: 2/13/2003	Date: 4/29/2009 5:09:16 PM Author: Ellen An IS won't necessarily show what I've noted. I didn't mean that. I only think that with such angles, there won't be any fire scintillation issue. Look at Brian's recent recuts. So the only thing I want to see with IS/ASET is if the facets are nicely aligned, and if there is not too much obstruction that could be caused by slightly painting the girdle (if a diamond is slightly painted, it is possible that the GIA doesn't mention it). I also ask for IS/ASET because we all know GIA numbers are rounded, so the picture will tell us if there is any light return issue with this diamond. Stephan
Posted: 4/29/2009 5:18:43 PM

P: 4/29/2009 7:43:08 PM
strmrdr Ideal Rock Total Posts: 23,296 Last Post: 10/9/2009 Member Since: 11/1/2003	I am going to assume that this is actually degrees... Crown: 33% Pavilion: 40.8% ie 33 degrees and 40.8 degrees. The combo is pretty good. I would like the lowers to be in the 76.5-77% range which gia would round down to 75... If it was over 77.5 it would round up to 80. So likely it is ok there. With the 58 table and 33 crown it will tend towards the bright side rather than fiery. It is much better than a lot of gia EX cuts so im not worried about the cut grade. An IS would help. ........... Karl has joined the diamond trade and is now posting as Karl_K
Posted: 4/29/2009 7:43:08 PM

P: 4/29/2009 7:47:04 PM
strmrdr Ideal Rock Total Posts: 23,296 Last Post: 10/9/2009 Member Since: 11/1/2003	Date: 4/29/2009 5:08:00 PM Author: QueenMum Date: 4/29/2009 4:37:40 PM Author: Ellen It 'may' lack a bit of scintillation/possibly appear slightly glassy/possibly lack a bit of fire. Fire is difficult to discuss as there are differences between diffuse or spot lighting. To my eyes, slightly shallow diamonds have better and more intense fire under spot lighting than deep ones. Deep diamonds have better fire under diffuse lighting than shallow ones. But that is just what my only eye can see, the other one is blind. But what is even more constant to my eye is the lack of scintillation of steep/deep diamonds. Ellen is right but it is a matter of how much. In this case with decent optical symmetry and the correct lowers it is a small amount. It doesn't mean it wont be fiery, it will just lean towards the bright side. ........... Karl has joined the diamond trade and is now posting as Karl_K
Posted: 4/29/2009 7:47:04 PM

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