Faceting Design Diagram: 3.0 Butterfly – Beryl – Aquamarine, Emerald, Helidore, Bixbite, Goshenite, Morganite, Golden Beryl


Beryl (Aquamarine, Emerald, Helidore, Bixbite, Goshenite, Morganite, Golden Beryl)

3.0 Butterfly (MC11.JRG)
By Jeff R. Graham
Copyright 1999
89.5% Light Return
Angles for R.I. = 1.56
21 facets + 4 facets on girdle = 25
2-fold, mirror-image symmetry
96 index
L/W = 3.000 T/W = 2.478 T/L = 0.826
P/W = 0.645 C/W = 0.163
H/W = (P+C)/W+0.02 = 0.828
P/H = 0.779 C/H = 0.197
Vol./W^3 = 1.427

Addition # 4 – This is easy to cut, but care must be taken not to chip the long sharp keel. I use this design for long Beryl crystals, it works best if they have decent color to them. Can be cut in a different order if you want, 1cts+. This also works well in Tourmaline. Cut this in R.I. 1.56 to 1.93 without 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.