Color Change Sapphire Faceting Information

Color Change Sapphire is unique and change different colors with different lighting view. This is a source on guides for faceting color change sapphires.

1 Minute Read

Color Change Sapphire Faceting Information

Color Change (Sapphire)

Blue/red color change sapphire

Color: Purple, violet to red-violet, blue/purple, pink/red to blue/purple. about any combination is possible
Moh's Hardness: 8.5-9
Refractive Index: 1.766-1.774
Critical Angle: 34.62°
Specific Gravity: 3.99-4.01
Cleavage: None
Fracture: Conchoidal
Dispersion: .013
Heat Sensitivity: Can be… but is usually not a problem
Dichroism: strong, especially in darker colors
Birefringence (double refraction): Weak (.018)
Crystal structure: Hexagonal, trigonal, dipyramidal

Treatments: Assume about any Sapphire you see has been heated unless otherwise noted from the supplier. Heat treating to reduce silk is and improve colors is standard. Glass-filling voids in rubies (any sapphire) is not considered an acceptable treatment, by me at least.

What I prefer to polishing with: Zinc laps with 8,000 pre-polish and 50,000 polish.

Jeff's Comments: Orientation for the best color can take experience and is often not easy for a beginner. Be sure and examine your rough in all lighting conditions when deciding orientation for cutting. Be careful. Sapphire cuts and polishes faster on some sides of the crystal because the hardness varies depending on the direction. It typically will have some pits on some facets (depending on the crystal direction) that need to be polished out. Orientating on the "c" is usually better color. Quality rough is difficult to come by.

Synthetic is usually called corundum and is available in many colors.

Design Links: 4-Way Stop - This is great for saturated rough if you have a piece that will work in the shape.
Princess - Nice in about any material
Brilliant Pear - Good in any color

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.

Never Stop Learning

When you join the IGS community, you get trusted diamond & gemstone information when you need it.

Become a Member

Get Gemology Insights

Get started with the International Gem Society’s free guide to gemstone identification. Join our weekly newsletter & get a free copy of the Gem ID Checklist!