Stone Hunting

[Nervis]

Firstly, what a great forum... I''ve enjoyed auditing everyone''s knowledge.

Now, to the stones...

I was at the jeweler''s today (the one who is setting the stone) and she showed me a number of round brilliants. The best of the bunch lists as follows:

(GIA)
Measurements: 7.19 - 7.26 x 4.25 mm
Carat Weight: 1.33
Color Grade: G
Clarity Grade: VS2
Cut Grade: Very Good
Depth: 58.8 %
Table: 57 %
Crown Angle: 30°
Crown Height: 12.5 %
Pavilion Angle: 40.8°
Pavilion Depth: 43 %
Star length: 50 %
Lower Half: 75 %
Girdle: Medium to Slightly Thick, Faceted
Culet: None
Polish: Excellent
Symmetry: Excellent
Fluorescence: None


Obviously the crown degree is lower than most folks'' sweet spot (and my own... I thought) but this stone seemed to out-perform higher cuts with the added bonus of appearing as large as many 1.5 cts.

I plunked in the numbers and it scores 1.7 in the BIC range on the HCA... whatever that means.

Given that I like its performance and price, should I be concerned with the shallow crown? Also, how does it stack up to the following, similarly priced WF stone?

(AGS)
Measurements: 6.96-6.98X4.27
Carat Weight: 1.273
Color Grade: F
Clarity Grade: VS2
Cut Grade: AGS Ideal 0
Depth %: 61.3
Table %: 56.4
Crown Angle: 34.6
Crown %: 15.1
Star : 54
Pavilion Angle: 40.6
Pavilion %: 42.7
Lower Girdle %: 78
Girdle: Thin to Medium Faceted
Light Performance: 0
Polish: Ideal
Symmetry: Ideal
Culet: Pointed
Fluorescence: Negligible


Thanks!

 

[Stone-cold11]

You saw the effect of the BIC yourself. It means Brilliant Ideal Cut. A standard ideal stone, such as the ACA is call the TIC. Brilliant cut usually has a larger face up then the traditional ideal cut. It sacrifice fire of the stone for more light return.

Another thing to worry about this BIC stone in particular is that it is in the pendant and ear-ring stone range. Stones in this range will be more affected by observer''s shadow, this will result in the stone darkening when the stone is observed too closely.

The ACA is a TIC, AGS0. Also it will be a Hearts and Arrow stone meaning it will have ideal optical symmetry, which can result in better optical performance.

 

[Nervis]

Thanks for the response...

So it sounds like I''d have to see these stones next to each other to discern optical performance?

 

[Lorelei]

Its a shallow diamond, if you want to buy it, make the sale final on it checking out with an independant appraisal. Shallow crowns can be prone to chipping in some cases, you might be ok with this one but I would recommend you get an independant appraiser to look at it to be on the safe side. Personally I would advise look at some more balanced stones such as AGS0 cut grade ( Jareds sell them if there is one in your area) so you can see what appeals to you most.