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


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

Penta Brilliant (MC82.JRG)
By Jeff R. Graham
Copyright 2002
86.5% Light Return
Angles for R.I. = 1.62
86 facets + 5 facets on girdle = 91
5-fold, mirror-image symmetry
80 index
L/W = 1.051 T/W = 0.369 T/L = 0.351
P/W = 0.470 C/W = 0.284
H/W = (P+C)/W+0.02 = 0.774
P/H = 0.607 C/H = 0.367
Vol./W^3 = 0.274

Addition # 7 – This is great in light to medium colored Quartz with no changes. Cut this in refractive indexes 1.54 to 2.14 with no changes. This is really nice in light Beryl. C2 on the crown is just cut to center point like P1 is.


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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