Faceting Design Diagram: Three Blade Triangle – Sapphire / Corundum – Ruby, Ceylon, Padparadschah, Pink, Yellow, Green


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

Three Blade Triangle (SAP1.JRG)
By Jeff R. Graham
Copyright 1994
82.5% Light Return
Angles for R.I. = 1.76
88 facets + 15 facets on girdle = 103
3-fold, mirror-image symmetry
96 index
L/W = 1.028 T/W = 0.507 T/L = 0.494
P/W = 0.398 C/W = 0.193
H/W = (P+C)/W+0.02 = 0.611
P/H = 0.652 C/H = 0.315
Vol./W^3 = 0.199

Gram Book 1 – This triangle has a lot of facets and should be cut in a medium to large size stone. This is really designed for man-made materials. It is a harder design to cut than some, pay attention to the meets. Any color material in light to medium color, 2-16cts. Cut in refractive index 1.78 to 2.14 (82%) 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.