Faceting Design Diagram: Dutch Pedals – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

Dutch Pedals (MIR2.JRG) Dutch petals in Zambain Tourmaline
By Jeff R. Graham
Copyright 2004
92.6% Light Return
Angles for R.I. = 1.62
56 facets + 8 facets on girdle = 64
8-fold, mirror-image symmetry
96 index
L/W = 1.000 P/W = 0.435 C/W = 0.211 H/W = (P+C)/W+0.02 = 0.666
P/H = 0.652 C/H = 0.317
Vol./W^3 = 0.213

Addition # 9 – This is designed to be cut in a large stone. On a small stone the C5 can be omitted, also a table can be added on very large stones. Note: Cut C1 to about the normal girdle thickness, do not make the point too sharp because it will chip. This is very quick and fairly easy cut, but depending on how you cut the C1 there may be some adjusting needed. Cut in refractive indexes 1.54 to 2.14 with no changes. Hint: Line the crown up using the C2, before cutting the C1 in.

 

 


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.