3-Triangle: Faceting Design Diagram

Sapphire / Corundum (Ruby, Ceylon, Padparadschah, Pink, Yellow, Green)

3-Triangle (SAP17.JRG)
By Jeff R. Graham
Copyright 1998
75% Light Return
Angles for R.I. = 1.76
34 facets + 6 facets on girdle = 40
3-fold, mirror-image symmetry
96 index
L/W = 1.155 T/W = 0.681 T/L = 0.590
P/W = 0.420 C/W = 0.217
H/W = (P+C)/W+0.02 = 0.657
P/H = 0.640 C/H = 0.330
Vol./W^3 = 0.239

Addition # 3 - The crown can be raised as high as 52 or cut as shallow as 42 degrees without changing the light return. This is good for about any material depending on the color. It's good for earrings especially, 1-6cts. Man- made Sapphire and Spinel works…

Random - Cosine - ISO

Detailed faceting instructions by Jeff Graham available at The Rock Peddler