Faceting Design Diagram: Diamond Back – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

Diamond Back (CHECK72.JRG)Diamond Back cut in Maderia Citrine by Tony Carson
By Jeff R. Graham
Copyright 2003
81.5% Light Return
Angles for R.I. = 1.62
27 facets + 6 facets on girdle = 33
2-fold, mirror-image symmetry
96 index
L/W = 1.33 T/W = 0.590 T/L = 0.457
P/W = 0.418 C/W = 0.146
H/W = (P+C)/W+0.02 = 0.584
P/H = 0.716 C/H = 0.250
Vol./W^3 = 0.217

Addition # 8 – Cut in refractive indexes 1.54 (78.4%) to 2.14 with no changes. This is a neat one, named after a local varmit we have in Tucson in the summer- time (rattlesnakes). This cuts fast and is good in about any material. The L/W on this can vary a bit with no problem.

 


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.