Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)
Poppy (CHECK74.JRG)
By Jeff R. Graham
Copyright 2003
86.6% Light Return
Angles for R.I. = 1.62
31 facets + 8 facets on girdle = 39
2-fold, mirror-image symmetry
96 index
L/W = 1.233 T/W = 0.462 T/L = 0.374
P/W = 0.396 C/W = 0.166
H/W = (P+C)/W+0.02 = 0.582
P/H = 0.681 C/H = 0.285
Vol./W^3 = 0.196
Addition # 8 – Cut this in refractive indexes 1.62 to 1.93 with no changes. This is fast and easy, good for a novice who wants to try a checker board. I like this in any medium color and it works best in a medium size stone.
Random – Cosine – ISO
Detailed faceting instructions by Jeff Graham available at The Rock Peddler
IGS Become Member