Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)
Shutter (DOME26.JRG)
By Jeff Graham
Copyright 2007
82.4 % Light Return
Angles for R.I. = 1.62
65 facets + 8 facets on girdle = 73
8-fold symmetry
96 index
L/W = 1.000 T/W = 0.211 T/L = 0.211 P/W = 0.415 C/W = 0.315
H/W = (P+C)/W+0.02 = 0.750 P/H = 0.553 C/H = 0.420
Vol./W^3 = 0.259
PAVILION
CROWN
Addition # 13 – Cut in refractive indexes 1.62 to 2.14 with no changes. This is designed for light saturated rough, and is best cut in a large stone. The light flash is very interesting and this is pretty unique.
Detailed faceting instructions by Jeff Graham available at The Rock Peddler
IGS Newsletter