Spike: Faceting Design Diagram

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

Spike (DOME38.JRG)
By Jeff R. Graham
Copyright 2007
82.8% Light Return
Angles for R.I. = 1.62
61 facets + 10 facets on girdle = 71
5-fold, mirror-image symmetry
80 index
L/W = 1.025 T/W = 0.190 T/L = 0.185 P/W = 0.404 C/W = 0.350
H/W = (P+C)/W+0.02 = 0.774 P/H = 0.523 C/H = 0.452
Vol./W^3 = 0.269

PAVILION

CROWN

Addition # 13 - Cut in refractive indexes 1.62 to 2.14 with no changes. This is interesting and works well in light to medium saturated material. It is not difficult to cut and I like it in Peridot or Tourmaline.

Detailed faceting instructions by Jeff Graham available at The Rock Peddler