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Slightly shallow RB has a HCA score of 0.8. Is it any good?

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singapore

Rough_Rock
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Jun 6, 2006
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Hi all, i was just wondering about the stone's specs below. I know that i have asked you guys before but i ran the specs through HCA and it turned out a score of 0.8. Have also attached a print screen of the HCA results. My question is that i know the stone is a little shallow compared to most stones, hence the 0.8 HCA score. I have seen the stone and it is bright and sparkly. How different is it visually if i were to compare a stone that is 0.8 and to a regular spec stone where the table is 56% and depth at 61% and that the HCA score is at 1.3 where most people consider it is an ideal stone. And lastly, what is more ideal of a stone? A shallow stone with a GIA graded excellent cut or a regular high crown stone that is also graded GIA excellent? Hope to hear from you experts out there. thank you.

GIA Report Number: 14575194
Report Type: GIA Diamond Grading Report
Date of Issue: March 15 2011
Round Brilliant
Measurements: 7.47 - 7.49 x 4.46 mm

Carat Weight: 1.50 carat
Color Grade: F
Clarity Grade: VVS2
Cut Grade: Excellent

Proportions:
Depth: 59.7%
Table: 58%
Crown Angle: 33.0°
Crown Height: 13.5%
Pavilion Angle: 40.8°
Pavilion Depth: 43.0%
Star length: 50%
Lower Half: 75%
Girdle: Thin to Medium (3.0%)
Culet: None

Finish:
Polish: very good
Symmetry: very good
Fluorescence: None
Key to symbols: pinpoint.

Screen Shot 2011-10-02 at 9.44.19 PM.png
 
Re: Slightly shallow RB has a HCA score of 0.8. Is it any go

singapore|1317565579|3031151 said:
Hi all, i was just wondering about the stone's specs below. I know that i have asked you guys before but i ran the specs through HCA and it turned out a score of 0.8. Have also attached a print screen of the HCA results. My question is that i know the stone is a little shallow compared to most stones, hence the 0.8 HCA score. I have seen the stone and it is bright and sparkly. How different is it visually if i were to compare a stone that is 0.8 and to a regular spec stone where the table is 56% and depth at 61% and that the HCA score is at 1.3 where most people consider it is an ideal stone. And lastly, what is more ideal of a stone? A shallow stone with a GIA graded excellent cut or a regular high crown stone that is also graded GIA excellent? Hope to hear from you experts out there. thank you.

GIA Report Number: 14575194
Report Type: GIA Diamond Grading Report
Date of Issue: March 15 2011
Round Brilliant
Measurements: 7.47 - 7.49 x 4.46 mm

Carat Weight: 1.50 carat
Color Grade: F
Clarity Grade: VVS2
Cut Grade: Excellent

Proportions:
Depth: 59.7%
Table: 58%
Crown Angle: 33.0°
Crown Height: 13.5%
Pavilion Angle: 40.8°
Pavilion Depth: 43.0%
Star length: 50%
Lower Half: 75%
Girdle: Thin to Medium (3.0%)
Culet: None

Finish:
Polish: very good
Symmetry: very good
Fluorescence: None
Key to symbols: pinpoint.

http://www2.gia.edu/reportcheck/index.cfm?fuseaction=home.showReportVerification&reportno=14575194&weight=1.50

Are there differences between stones of different proportions? Absolutely. Will YOU see the differences? We can't answer that. What will you think of the differences, which type will you like more? We can't answer that either. Take a couple of hours one evening and go to your local jeweller, and compare that stone to others of various proportions in different types of lights - in the spotlights, in direct sunlight by a window and diffuse office light, see what your eyes consistently prefer.

Neither type is objectively "better", just different. Which you like better - if you notice any difference - is, as I said, something you must determine in-person.

Nothing wrong with the numbers on that stone, pav is fine - it's not "shallow", even assuming some averaging and rounding. Nothing of note on the report. Without more info - full scan, pics, professional review we can't tell you much more than that - GIA averages proportions around eight sections of stone, then rounds, so we don't know what sorts of ranges went into the rounded averages printed on the report. If you've seen it and you like it, and you've compared it to other stones and you like it, you're making an educated decision :))
 
Re: Slightly shallow RB has a HCA score of 0.8. Is it any go

Looks promising...
 
Re: Slightly shallow RB has a HCA score of 0.8. Is it any go

Hi Yssie and Amy blings, thank you for your reply. Sorry i used the wrong term when i mentioned that the stone was shallow, what i was trying to say was that the stone has a slightly lower crown than usual, i read in the posts that with a slightly lower crown, there would be less fire and scintillation, but with a lower crown, its also brighter as well, do advice if this is correct. And that was the thing, with this mindset, i went to look at the stone and it was both bright and sparkly, and it got me wondering how much different can it be if i were to come across a stone of more ideal proportions like a CA of 34 instead of 33. Also i spent more time looking at the stone in office diffuse lighting and regular sunlight, since in reality it would have spent more time in those of situations. So can i assume, that a stone with a higher crown, it will have more fire and scintillation but it wont look as "bright" in regular diffuse lighting and regular sunlight compared to a stone with a lower crown?
 
Re: Slightly shallow RB has a HCA score of 0.8. Is it any go

singapore|1317600201|3031609 said:
Hi Yssie and Amy blings, thank you for your reply. Sorry i used the wrong term when i mentioned that the stone was shallow, what i was trying to say was that the stone has a slightly lower crown than usual, i read in the posts that with a slightly lower crown, there would be less fire and scintillation, but with a lower crown, its also brighter as well, do advice if this is correct. And that was the thing, with this mindset, i went to look at the stone and it was both bright and sparkly, and it got me wondering how much different can it be if i were to come across a stone of more ideal proportions like a CA of 34 instead of 33. Also i spent more time looking at the stone in office diffuse lighting and regular sunlight, since in reality it would have spent more time in those of situations. So can i assume, that a stone with a higher crown, it will have more fire and scintillation but it wont look as "bright" in regular diffuse lighting and regular sunlight compared to a stone with a lower crown?


Your last sentence just about sums up the Cliff Notes version.

In reality - like I said, Cliff Notes doesn't give you the whole story, and won't tell you anything about what you see and prefer to see.

In regular ol' white flat-panel office light an RB with a 37 crown would still be white - that's just one of those extreme lighting types! And both would be fireballs on a bright sunny day. On cloudy days, in rooms with mixed lighting - yes, you may find this stone is brighter (more white light return) but shows less colour than one of similar size w/ higher crown, esp if there is a large range of crown angles that averages then rounds up to 33 (so low optical symmetry, which also means smaller average facet size, which will also contribute to white light return...).

Scintillation - is a different discussion I think. Scintillation = facets changing from black to white to black again as you move the stone, like a chessboard. Both stones will have scintillation, what you see when the facets change colour depends on what sorts of proportions you're talking about - a stone w/ 75lgf like this one will have thicker arrowshafts that stand out more when you rock the stone than a stone w/ 85lgf, say. Different personalities.
 
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