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

Reverse "P" (TLINE.JRG)
By Jeff R. Graham
Copyright 1994
76.5% Light Return
Angles for R.I. = 1.62
43 facets + 6 facets on girdle = 49
6-fold, mirror-image symmetry
96 index
L/W = 1.155 T/W = 0.559 T/L = 0.485
P/W = 0.442 C/W = 0.213
H/W = (P+C)/W+0.02 = 0.675
P/H = 0.655 C/H = 0.315
Vol./W^3 = 0.263

Gram Book 1 - This design is unusual and not hard to cut. The P3 & P4 facets are a different size which gives the stone a very different flash. P4 facets cut very fast so watch out, 1/2-4cts any color med to light material. This design is surprisingly nice, give it a try... Cut in refractive index 1.62 to 1.93 (77.5%) with no changes.

 

 

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