Faceting Design Diagram: 8 Round Brilliant – Quartz – Citrine, Amethyst, Ametrine, Smokey, Rose


Quartz (Amethyst, Citrine, Ametrine, Smokey, Rose)

8 Round Brilliant (QTZ2.JRG) 5.32 carat Tourmaline
By Jeff R. Graham
Copyright 1993
78.5% Light Return
Angles for R.I. = 1.54
57 facets + 16 facets on girdle = 73
8-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.490 T/L = 0.490
P/W = 0.435 C/W = 0.168
H/W = (P+C)/W+0.02 = 0.623
P/H = 0.698 C/H = 0.270
Vol./W^3 = 0.226

Addition # 1 – This is a pretty standard round brilliant, a nice stone in any size and easy to cut. The crown at 42 degrees is as high as you can go and still have good light return in low R.I. materials. Cut in refractive indexes 1.54 to 1.93 (92.2%) with no changes.


Random – Cosine – ISO

Detailed faceting instructions by Jeff Graham available at The Rock Peddler

Gram Faceting Archive of Information
This edited version of an article by the late Jeff Graham is part of a special archived informational series from Gram Faceting. Used with permission.