Faceting Design Diagram: Diamonds & Bonz’s – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

Diamonds & Bonz’s (CHECK52.JRG)
By Jeff R. Graham
Copyright 2002
90.5% Light Return
Angles for R.I. = 1.62
41 facets + 8 facets on girdle = 49
2-fold, mirror-image symmetry
96 index
L/W = 1.023 T/W = 0.301 T/L = 0.295
P/W = 0.470 C/W = 0.202
H/W = (P+C)/W+0.02 = 0.692
P/H = 0.679 C/H = 0.292
Vol./W^3 = 0.304

Addition # 8 – Cut this in refractive indexes 1.62 to 1.93 with no changes. This is a little complicated, but not too hard to cut. The crown facets cut fast, especially on a small stone. This works well in about any material.

 

 

 


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.