Home Rough Bargains Equipment Books Online Designs Just Ask Jeff Order News List Contact Me Links
Amethyst Aquamarine Beryl Citrine Emerald Garnet Opal Peridot Sapphire Scapolite Spinel Sunstone Topaz Tourmaline Quartz Zircon
Beginner's Page New Stuff Odds & Ends Specials Parcels Synthetics
Cut Gemstones Gemological Information Gemstone Pricing Guides How to buy Gemstones

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

Cross Mod-Square (TLINE7.JRG)
By Jeff R. Graham
Copyright 1993
83.8% Light Return
Angles for R.I. = 1.62
77 facets + 12 facets on girdle = 89
4-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.527 T/L = 0.527
P/W = 0.486 C/W = 0.202
H/W = (P+C)/W+0.02 = 0.709
P/H = 0.686 C/H = 0.286
Vol./W^3 = 0.304

Addition # 1 - This design has very deep breaks. In order not to waste material cut a preform, see heading for measurements. The depth of this design helps light material and gives the stone a nice shape, 1-18cts. Cut in refractive indexes 1.62 to 1.93 (86.8%) with no changes. Works well in Topaz also...

 

 


Random - Cosine - ISO

Return to OnLine Design Index

Home Rough Bargains Equipment Books Online Designs Just Ask Jeff Order News List Contact Me Links


Copyright 1998-2007 Gram Faceting - All Rights Reserved.