Faceting Design Diagram: Asterism Revisited – Tourmaline, Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

Asterism Revisited Jeff Graham Facet Design 1 Asterism Revisited Jeff Graham Facet Design 2

Asterism Revisited (DOME10.JRG)
By Jeff R. Graham
Copyright 2007
87.7% Light Return
Angles for R.I. = 1.62
145 facets + 12 facets on girdle = 157
12-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.309 T/L = 0.309 P/W = 0.405
C/W = 0.336 H/W = (P+C)/W+0.02 = 0.761 P/H = 0.532 C/H = 0.441 Vol./W^3 = 0.288

Addition # 13 – Cut this in refractive indexes 1.62 to 2.14 with no changes. This is not hard to cut, but takes a while. Lightly saturated materials work best.

Asterism Revisited Jeff Graham Facet Design 3

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.