Suggested Faceting Angles for Various Man-Made Materials

CA= Critical Angle; RI= Refractive Index

Angles listed as: Crown Mains/Pavilion Mains
Courtesy of the Facet Shoppe- John and Barbara Franke

MATERIAL
RI
CA
Vargas
M.D.R.
Schlagel

Beryl
1.58
39.5
42/43
42/43
37/41
Chrysoberyl
Alexandrite
1.75
35.0
40/42
37/42
36/340
Corundum
1.76
34.5
40/42
37/42
36/40
Cristinite(tm)
1.62
38
41/42
37/42
42/43
GGG (Garnet)
2.00
30.5
37/41
-
-
Glass
varies
varies
42/43
-
-
Quartz
1.55
40
42/43
42/43
38/42
Rutile
2.6
22
33/40
-
-
Silicon Carbide
moissanite
2.65
22
32/40
37/42
35/39
Spinel
1.72
35.5
40/42
37/42
35/39
Strontium Titanate
2.41
24.5
3540
-
-
YAG (Garnet)
1.83
33
38/41
-
-

Remember the Critical Angle (CA) is what you want to be aware of when cutting the pavilion. Cutting pavilion facets at an angle less than the critical angle can cause your gem to "fisheye" or dump light rays out of the pavilion instead of reflecting them back through the crown. The Refractive Index (RI) is a ratio of the speed of light within a substance compared with the speed of light in air. It is pretty technical but the higher the RI the more sparkle, basically. There are many other terms and conditions that effect the color and sparkle of your finished gem and you may find it worth your while to buy a comprehensive reference or borrow one from the local library to learn these things. You can learn from your own experiments- discover the angles *you* like the best for each material!

Use this opportunity to check out our quality faceting rough or take advantage of our discount prices on our full line of quality lapidary equipment and supplies.
We offer prompt, courteous service, shipping on most items within 24 hours,
a no-nonsense satisfaction guarantee, and excellent after-sale support.
Rough Gemstone for Sale Cut Gemstones for Sale Jewelry for Sale
Specials Lapidary Supplies and Equipment Easy Mount Settings
VISA Logo.MasterCard Logo.

Ordering is easy at the Facet Shoppe; choose the way that works best for you...
How To Order
Back to the Facet Shoppe Home Page
Facet Shoppe

Comments or Questions? E-mail us Now!

Page maintained by John Franke, facet@gemcutter.com. Copyright(c) 1998-2008
Updated: 8-24-08 All Rights Reserved.