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


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

Hubcap (TLINE25.JRG)
By Jeff R. Graham
Copyright 1995
75% Light Return
Angles for R.I. = 1.62
105 facets + 8 facets on girdle = 113
8-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.497 T/L = 0.497
P/W = 0.441 C/W = 0.176
H/W = (P+C)/W+0.02 = 0.637
P/H = 0.692 C/H = 0.276
Vol./W^3 = 0.205

Gram Book 1 – The table is about 50% and it helps a lot if you rough it in before cutting the C4 facets, because they meet. This design is nice in about any color, 1-8cts. The reflection is higher than the ray trace indicates. Cut in refractive index 1.62 to 2.14 (85.3%) 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.