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

About the author
Jeff R. Graham
The late Jeff Graham was a prolific faceter, creator of many original faceting designs, and the author of several highly-regarded instructional faceting books such as Gram Faceting Designs.
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