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

Four Arrows (MC81.JRG)
By Jeff R. Graham
Copyright 2002
91.8% Light Return
Angles for R.I. = 1.62
49 facets + 8 facets on girdle = 57
4-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.244 T/L = 0.244
P/W = 0.445 C/W = 0.203
H/W = (P+C)/W+0.02 = 0.668
P/H = 0.666 C/H = 0.304
Vol./W^3 = 0.260

Addition # 7 – This is nice in about any material, I often use it for cutting dark stones. Cut in refractive indexes 1.62 to 2.14 with no changes. This makes good earrings, easy to set and are low profile so they wear well.


Random – Cosine – ISO

Detailed faceting instructions by Jeff Graham available at The Rock Peddler