Faceting Design Diagram: Boxed – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

Boxed (TLINE20.JRG)
By Jeff R. Graham
Copyright 1995
81.5% Light Return
Angles for R.I. = 1.62
43 facets + 8 facets on girdle = 51
2-fold, mirror-image symmetry
96 index
L/W = 1.203 T/W = 0.525 T/L = 0.436
P/W = 0.454 C/W = 0.269
H/W = (P+C)/W+0.02 = 0.743
P/H = 0.611 C/H = 0.362
Vol./W^3 = 0.379

Gram Book 1 – It helps if you cut in a temporary girdle P4(G) and P6(G)in a preform L/W=1.20 rectangle. Then cut P1,P2,P3 to center point and adjust the girdle if need be. The P8’s cut fast, light to medium material 1-6cts. Cut in refractive index 1.62 to 1.76 (85%) with no changes.

 

 


Random – Cosine – ISO

Detailed faceting instructions by Jeff Graham available at The Rock Peddler

Gram Faceting Archive of Information
This edited version of an article by the late Jeff Graham is part of a special archived informational series from Gram Faceting. Used with permission.