Faceting Design Diagram: T-Tipped Tri – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)

T-Tipped Tri (TLINE38.JRG)
By Jeff R. Graham
Copyright 1997
78.4% Light Return
Angles for R.I. = 1.62
58 facets + 6 facets on girdle = 64
3-fold, mirror-image symmetry
96 index
L/W = 1.155 T/W = 0.556 T/L = 0.481
P/W = 0.486 C/W = 0.209
H/W = (P+C)/W+0.02 = 0.715
P/H = 0.679 C/H = 0.293
Vol./W^3 = 0.260

Addition # 2 – This is hard to cut because of the small crown facets. It should be cut in a larger size and lighter material. The C4,C5 facets are not cut to center point, and on a smaller stone might have to be hand-lapped, 3- 16cts. Cut in refractive indexes 1.62 to 1.93 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.