Faceting Design Diagram: Optimal Hex – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

Optimal Hex (B23.JRG)
By Jeff R. Graham
Copyright 2001
90.5% Light Return
Angles for R.I. = 1.62
61 facets + 6 facets on girdle = 67
3-fold, mirror-image symmetry
96 index
L/W = 1.073 T/W = 0.488 T/L = 0.455
P/W = 0.472 C/W = 0.153
H/W = (P+C)/W+0.02 = 0.645
P/H = 0.732 C/H = 0.237
Vol./W^3 = 0.246

Addition # 5 – This is fast and fairly easy to cut and works well in almost any material. This is designed for the “c” axis crystal shape that is fairly common in Tourmaline. It will work in R.I. 1.62 to 1.76 (88.9%) 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.