Zincite Faceting Information
A guide to Zincite Faceting Information. Essential information on Zincite faceting that includes tips on cuts and polishes together with helpful details.
Zincite (zinc oxide)
Color: Orange, red and yellow, leek-green, light blue to colorless. Moh's Hardness: 4-4.5
Refractive Index: 2.02
Critical Angle: 29.67°
Specific Gravity: 5.6
Cleavage: Perfect
Fracture: Subconchoidal, brittle
Dispersion: .127
Heat Sensitivity: Low
Birefringence (double refraction): Medium (.016)
Crystal Structure: Hexagonal
Treatments: None
What I prefer to polishing with: Tin lap with Alumina oxide. Zinc laps with 8,000 pre-polish and 50,000 polish. Specta Ultalaps work pretty well. It tends to scratch and chip during polishing and can be problematic.
Jeff's Comments: Zincite is brittle, so be careful not to shock the stone while cutting and use fine laps for roughing in.
Design Links: 4-Way Stop - This is great for saturated rough if you have a piece that will work in the shape.
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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