Find your diamond
Find your jewelry
shape
carat
color
clarity

Is >80% lower girdle bad? - DiamCalc assistance

RayEarth

Rough_Rock
Joined
Mar 21, 2011
Messages
46
Pulling my hair out trying to decide between the two diamonds (same color/clarity/price). Is anyone able to run the numbers through DiamCalc for me? Diamond 1 is obviously bigger but I wonder if 81% lower girdle facets is too big (it also causes a split in the hearts image below). I also hear reports that AGS/GIA's new grading system will penalize lower girdle >80%?

Code:
                   Diamond 1          Diamond 2
Weight.............1.803              1.726
Diameter...........7.80               7.69
Total depth........61.80              61.4
Table size.........57.4               56.7
Crown angle %......35.19              34.8
Crown height.......15.06              15.0
Pavilion angle %...40.80              40.9
Pavilion depth.....43.14              43.0
Star length %......48.1               52.0
Lower halves %.....81.0               78.0
Girdle Min %.......2.08               1.7
Girdle Max %.......2.48               2.3
Here are some comparison ASET and H&A shots (Diamond 1 on the left, Diamond 2 on the right).

2_18.jpg
1_20.jpg
 

yssie

Super_Ideal_Rock
Premium
Joined
Aug 14, 2009
Messages
20,749
No worries on 81lgf - truly!! GIA rounds to 5% anyway - so a GIA "80" could be 82, no way of knowing without more info. If you like the look of skinny arrows and more "splintery" light return, for lack of better wording, than a stone w/ thicker arrows then go for it!

The hearts optical symmetry pattern is a function of pavilion patterning - hence the effects of different lower girdle facet/mains ratios. Some brands (WF ACA for example) require that all proportions fit within specific ranges so that all hearts pics look very similar in terms of hearts shapes, V thickness, no or very small cleft - and because of those proportions restrictions those stones will also show similar type of light return. other vendors like GOG will accept stones of all sorts of proportions as "H&A" as long as they show clear radial symmetry in patterning, and different stones w/ different proportions can perform quite differently! One type isn't better than the other - just different models of branding/sales, and what's best for you really depends on what you prefer to see.

Would request hearts photo retake of the GOG if it is being sold as H&A.
 

RayEarth

Rough_Rock
Joined
Mar 21, 2011
Messages
46
Thanks Yssie

It's always a bit difficult as I'm in Australia and trying to buy a rock remotely by using only numbers and pictures! I guess the other thing that is bugging me a little is BScope is returning only H2 on "Brilliance" (VH for sparkle and scintillation). I know BScope is not the most accurate machine around that's why I was wondering if someone can help run the DiamCalc numbers.

But your explanation at least puts my mind slightly more at ease re Diamond 1....
 

yssie

Super_Ideal_Rock
Premium
Joined
Aug 14, 2009
Messages
20,749
RayEarth|1306893733|2935000 said:
Thanks Yssie

It's always a bit difficult as I'm in Australia and trying to buy a rock remotely by using only numbers and pictures! I guess the other thing that is bugging me a little is BScope is returning only H2 on "Brilliance" (VH for sparkle and scintillation). I know BScope is not the most accurate machine around that's why I was wondering if someone can help run the DiamCalc numbers.

But your explanation at least puts my mind slightly more at ease re Diamond 1....


Well - plastic suit zipped up - personally think BScope's initials are rather apt for the things some people/vendors (yes, I am thinking of one in particular) use it for, and claim that it proves... Like any other tool it has uses and failings, and it's dangerous to put too much faith in one tool without recognising what it can and can't reliably be used for!

GOG has a good tutorial on BScope - http://www.goodoldgold.com/Technologies/BrillianceScope/BrillianceScopeStrengths/ should help explain some discrepancies. Long story short - Bscope will favour the light return from a princess over that from say a chunky, large faceted cushion. Obviously not everyone prefers princesses over chunky cushions IRL.

Both of those ASET photos look picture perfect for how I would expect a very nice bright RB to look, assuming they are actual photos and not computer simulations.
 

RayEarth

Rough_Rock
Joined
Mar 21, 2011
Messages
46
Is the star/lpf of 48.1/81 workable? Star % of 48.1 seems to be on the shorter side?
 

yssie

Super_Ideal_Rock
Premium
Joined
Aug 14, 2009
Messages
20,749
RayEarth|1306928724|2935277 said:
Is the star/lpf of 48.1/81 workable? Star % of 48.1 seems to be on the shorter side?
Is fine - pics in this review will detail: http://www.goodoldgold.com/Articles/MinorFacets/


Keep in mind that it's not any particular measurement, or pair of measurements - it's how they work together with all the stone's other proportions, and whether they all work well or not. You are doing your due diligence - but I think wrt separating good from bad stones it's toeing the line into worrying too much ;)) GIA also rounds star to 5%. You have ASET photos as well which show brightness at one particular (face-up) angle - they show actual brightness that results from all the stone's proportions working together - they are one level of confirmation that all the stone's proportions *do* work well together, and for more information on what star/lgf combo means specifically the tutorial above is a good resource
 

dreamer_dachsie

Super_Ideal_Rock
Joined
Dec 16, 2007
Messages
24,364
You have selected two stones that fall into the top... ooooh... .o1% of diamonds cut on the market ;)) And they have remarkably similar stats. Trying to choose between them based on pictures and numbers when you get that level of specificity may be fun (if you are an analytic type.. or a bit of a masochist, take your pick :rodent: ) but I don't think it is a particularly valid exercise in terms of predicting which stone you would like more in person, for example. Both of the stones you have chosen will be exceptional and will look very similar. But they may have slightly different "flavours" in terms of their appearance, due to subtle differences in their cuts, inclusing factors not evident in the numbers you have. Different personalities in diamonds are part of their appeal. But knowing which you prefer would likely mean owning both and living with them a while. Unless you are a true diamond nut, though, I think you can choose either one and be happy! The subtle differences in personality between these cuts is something that you likely would not notice anyways unless you become a serial diamond owner liek Yssie or I have been 8)

So I suggest you start using some other factors to help you choose. Color, clarity, mayeb the face up spread, does one vendor have a setting you like or other policies that appeal to you?

Or you can flip a coin ::)
 

yssie

Super_Ideal_Rock
Premium
Joined
Aug 14, 2009
Messages
20,749
Dreamer_D|1306951607|2935497 said:
You have selected two stones that fall into the top... ooooh... .o1% of diamonds cut on the market ;)) And they have remarkably similar stats. Trying to choose between them based on pictures and numbers when you get that level of specificity may be fun (if you are an analytic type.. or a bit of a masochist, take your pick :rodent: ) but I don't think it is a particularly valid exercise in terms of predicting which stone you would like more in person, for example. Both of the stones you have chosen will be exceptional and will look very similar. But they may have slightly different "flavours" in terms of their appearance, due to subtle differences in their cuts, inclusing factors not evident in the numbers you have. Different personalities in diamonds are part of their appeal. But knowing which you prefer would likely mean owning both and living with them a while. Unless you are a true diamond nut, though, I think you can choose either one and be happy! The subtle differences in personality between these cuts is something that you likely would not notice anyways unless you become a serial diamond owner liek Yssie or I have been 8)

So I suggest you start using some other factors to help you choose. Color, clarity, mayeb the face up spread, does one vendor have a setting you like or other policies that appeal to you?


Or you can flip a coin ::)

Yes - exactly!
 

RayEarth

Rough_Rock
Joined
Mar 21, 2011
Messages
46
Awesome - thanks a zillion guys. Understand that I'm probably over-analysing but it appears that PS has the tendency to make people do that if they wonder around this place for too long. :tongue:

I guess I'm just quite nervous being the first time I'm buying a diamond and this thing costs about 30k!

Last question if I may, the hearts image shows slight skew near the end (see photo below). Research on the forum suggest that this may be due to "facet yew". Is that correct? Is this something that I should be concerned about?

8400%20-%20hearts.jpg
 

Stone-cold11

Super_Ideal_Rock
Joined
Sep 9, 2008
Messages
14,069
Is it sold as a stone with superior optical symm? If not, that is what you pay for.
 

diamondseeker2006

Super_Ideal_Rock
Premium
Joined
Jan 11, 2006
Messages
55,806
RayEarth|1306980383|2935872 said:
No - $31,550. Is that a fair price? Not sure what the premium would be if the optical symmetry were to change from "premium" to "superior"?[/quote

I think you'll have to give the weight, color, and clarity for anyone to evaluate the price. =)

Good Old Gold is a wonderful vendor and I wouldn't hesitate to buy from them. In fact, I did! :bigsmile:
 
Be a part of the community It's free, join today!
    Celebratory Engagement Ring Upgrade And Bracelet
    Celebratory Engagement Ring Upgrade And Bracelet
    Chiguys's Cushion Cut Engagement Ring
    Chiguys's Cushion Cut Engagement Ring
    Archduchess Eleonore von Habsburg and Jérôme d’Ambrosio Royal Wedding
    Archduchess Eleonore von Habsburg and Jérôme d’Ambrosio Royal Wedding

Need Something Special?

Get a quote from multiple trusted and vetted jewelers.

Holloway Cut Advisor



Diamond Eye Candy

Click to view full-size image.
Top