Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)
Baron’s Choice (CHECK25.JRG)
By Jeff R. Graham
Copyright 2001
90.4% Light Return
Angles for R.I. = 1.62
65 facets + 8 facets on girdle = 73
4-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.211 T/L = 0.211
P/W = 0.534 C/W = 0.238
H/W = (P+C)/W+0.02 = 0.793
P/H = 0.674 C/H = 0.301
Vol./W^3 = 0.390
Addition # 6 – The corners of this design are made to be adjustable, but ideally they should be large enough to take a setting prong. This stone is designed for a large 10mm and up stone. P5 may need to be floated in as the corners vary.
Random – Cosine – ISO
Detailed faceting instructions by Jeff Graham available at The Rock Peddler
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.
