Tri-Angled Triangle: Faceting Design Diagram

Details, tips, and guide on Faceting Designs. Faceting Design Diagram by Jeff R. Graham that presents various cuts, this one is called "Tri-Angled Triangle"


Garnet (Pyrope, Rhodolite, Almandine, Spessartite, Grossular, Demantoid, Tsavorite)

Tri-Angled Triangle (GNETP18.JRG)
By Jeff R. Graham
Copyright 1993
78.1% Light Return
Angles for R.I. = 1.73
61 facets + 9 facets on girdle = 70
3-fold, mirror-image symmetry
96 index
L/W = 1.071 T/W = 0.517 T/L = 0.483
P/W = 0.429 C/W = 0.193
H/W = (P+C)/W+0.02 = 0.642
P/H = 0.668 C/H = 0.301
Vol./W^3 = 0.217

Gram 1 - This stone has better light return than the 80% that it shows. It works best when it is cut in light material, 1-8cts. This works well in Spinel, Sapphire and YAG.

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.

Never Stop Learning

When you join the IGS community, you get trusted diamond & gemstone information when you need it.

Become a Member

Get Gemology Insights

Get started with the International Gem Society’s free guide to gemstone identification. Join our weekly newsletter & get a free copy of the Gem ID Checklist!