Orthoclase Facet / Faceting Information

A great informational article about tips on Orthoclase Faceting. Covers Orthoclase Faceting related issues, news, research, and much more helpful details.

Home Learning Center Jewelry and Lapidary Cutting Information for Specific GemstonesOrthoclase Facet / Faceting Information

By Jeff R. Graham

Orthoclase Facet / Faceting Information

Orthoclase (Feldspar)

Color: Colorless, champagne to yellow
Moh's Hardness: 6-6.5
Refractive Index: 1.52-1.568
Critical Angle: 41.14°
Specific Gravity: 2.56-2.62
Cleavage: Perfect in 3 directions, can be a problem when cutting
Fracture: Uneven, somewhat brittle
Dispersion: .012
Heat Sensitivity: Moderate in my experience
Dichroism: Weak
Birefringence (double refraction): Weak to medium (.005-.01)
Crystal Structure: Monoclinic

Treatments: Generally none

What I prefer to polishing with: Cerium oxide with a Spectra Ultralap.

Jeff's Comments: Cuts and polishes easily, use a medium fine lap like a 600 grit for roughing in because a coarse lap can sometimes aggravate cleavage. Cleavage can be a problem, sharp corners have a tendency to chip out sometimes during cutting.

Design Notes: About any Quartz design will work well… I prefer a deeper design and often cut Barions.

Design Links: Tzar - High dome will help improve color and sparkle

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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Orthoclase Facet / Faceting Information