Faceting Design Diagram: Malt Square – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

Malt Square (B19.JRG)
By Jeff R. Graham
Copyright 1999
90.3% Light Return
Angles for R.I. = 1.62
53 facets + 8 facets on girdle = 61
4-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.612 T/L = 0.612
P/W = 0.522 C/W = 0.132
H/W = (P+C)/W+0.02 = 0.673
P/H = 0.775 C/H = 0.196
Vol./W^3 = 0.302

Addition # 5 – This cuts easy and works well in a medium colored material. It is not a high crown and works well with saturated materials. Cut this in R.I. 1.62 to 1.76 (86.5%) 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.