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

Cross Mod-Square (TLINE7.JRG)
By Jeff R. Graham
Copyright 1993
83.8% Light Return
Angles for R.I. = 1.62
77 facets + 12 facets on girdle = 89
4-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.527 T/L = 0.527
P/W = 0.486 C/W = 0.202
H/W = (P+C)/W+0.02 = 0.709
P/H = 0.686 C/H = 0.286
Vol./W^3 = 0.304

Addition # 1 - This design has very deep breaks. In order not to waste material cut a preform, see heading for measurements. The depth of this design helps light material and gives the stone a nice shape, 1-18cts. Cut in refractive indexes 1.62 to 1.93 (86.8%) with no changes. Works well in Topaz also...

 

 

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