Three Blade Triangle: Faceting Design Diagram

Details and guide on Faceting Designs. A Faceting Design Diagram by Jeff R. Graham that presents various cuts, this one is called "Three Blade Triangle".


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

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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