3-Triangle: Faceting Design Diagram
Detailed information and guide on Faceting Designs. A Faceting Design Diagram by Jeff R. Graham that presents various cuts, this one is called "3-Triangle".
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
Jeff R. Graham
The late Jeff Graham was a prolific faceter, creator of many original faceting designs, and the author of several highly-regarded instructional faceting books such as Gram Faceting Designs.
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