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

Long Diamond (CHECK67.JRG) Afgan Bi-Color Tourmaline
By Jeff R. Graham
Copyright 2003
84.5% Light Return
Angles for R.I. = 1.62
27 facets + 4 facets on girdle = 31
2-fold, mirror-image symmetry
96 index
L/W = 2.001 T/W = 0.967 T/L = 0.483
P/W = 0.420 C/W = 0.300
H/W = (P+C)/W+0.02 = 0.740
P/H = 0.567 C/H = 0.405
Vol./W^3 = 0.896

Addition # 8 – This is a good design for about any Tourmaline, it’s a nice change from a regular rectangle. This works best in 1.62 but can be cut in refractive index up to 2.14 with no changes.


Random – Cosine – ISO

Detailed faceting instructions by Jeff Graham available at The Rock Peddler