Faceting Design Diagram: Gram Barion Pear – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite

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

Gram Barion Pear (B42.JRG)
By Jeff R. Graham
Copyright 2001
86.2% Light Return
Angles for R.I. = 1.62
74 facets + 16 facets on girdle = 90
1-fold, mirror-image symmetry
96 index
L/W = 1.436 T/W = 0.677 T/L = 0.472
P/W = 0.624 C/W = 0.185
H/W = (P+C)/W+0.02 = 0.829
P/H = 0.753 C/H = 0.223
Vol./W^3 = 0.432

Addition # 5 – A lot of people have asked me for a Barion pear that performs well. Here it is… Cut in R.I. 1.62 to 1.93 (87.0%) with no changes. I recommend large and light materials for this design. The breaks are steep, set it from the ends. Notice the P21 & P22 do not meet breaks, these absorb any slack in case your L/W is off a bit. P22 can be fudged to meet breaks… I fudge.

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.