Faceting Design Diagram: Plus Six – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

Plus Six (CHECK2.JRG)10.06 carat Tourmaline
By Jeff R. Graham
Copyright 2001
90.2 % Light Return
Angles for R.I. = 1.62
23 facets + 6 facets on girdle = 29
6-fold, mirror-image symmetry
96 index
L/W = 1.155 T/W = 0.280 T/L = 0.243
P/W = 0.405 C/W = 0.181
H/W = (P+C)/W+0.02 = 0.606
P/H = 0.668 C/H = 0.299
Vol./W^3 = 0.232

Addition # 6 – This was designed for a rather large piece of Nigerian Tourmaline that I wanted to cut. The stone was six-sided with Rubellite outside with a peach center. I wanted something that would be bright and show off the unusual quality of the rough. I prefer checkerboards for material that is saturated and here is what I came up with. This works well in Garnet, darker Sapphire and most man-made materials.

 


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.