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

Framed Star (B5.JRG)
By Jeff R. Graham
Copyright 1999
85% Light Return
Angles for R.I. = 1.62
75 facets + 14 facets on girdle = 89
2-fold, mirror-image symmetry
96 index
L/W = 1.330 T/W = 0.839 T/L = 0.631
P/W = 0.621 C/W = 0.166
H/W = (P+C)/W+0.02 = 0.807
P/H = 0.770 C/H = 0.205
Vol./W^3 = 0.429

Addition # 5 - Cut to meet C5,C8. A preform is a good idea. Cut to center point then cut the girdle to meet P1, establishing shape, then breaks. Cut in R.I. 1.62 to 1.93 with no changes. On a smaller stone C11 can be left off...

 

 


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