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


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

Bethlaham Star (MC76.JRG)
By Jeff R. Graham
Copyright 2001
82.2% Light Return
Angles for R.I. = 1.62
45 facets + 6 facets on girdle = 51
2-fold, mirror-image symmetry
96 index
L/W = 1.335 T/W = 0.238 T/L = 0.179
P/W = 0.406 C/W = 0.274
H/W = (P+C)/W+0.02 = 0.700
P/H = 0.580 C/H = 0.391
Vol./W^3 = 0.269

Addition # 7 – This is really very nice. When cutting the crown cut C1,C3,C4,C5,C6 as evenly as you can, there are no meets. You may have to cut the crown a couple of times to get the tiers even.


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.