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: Medium (.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

Man-Made Links:
Synthetics - Index of Synthetic / Man-made Rough

Cubic Zirconia - Index to Cubic Zirconia
Blue
Clear/White
Golden/Topaz
Lavender
Peach
Pink
Red
Cubic Zirconia Special

Sapphire (Corundum) - Index of Man-made Sapphire Rough
Burma Pink - Man-made Sapphire boules
Ceylon Blue - Man-made Sapphire boules
Color Change - Man-made Sapphire boules
Cranberry - Man-made Sapphire boules
Imperial - Man-made Sapphire boules
Padaparadschah - Man-made Sapphire boules
Ruby - Man-made Sapphire boules
White/Clear - Man-made Sapphire boules

YAG (man-made Garnet) - Index to YAG
Colorless - White, clear YAG
Green/Teal - Green/Teal YAG
Hot Yellow - Chrysoberyl color YAG
Pink - Pink YAG
Pink/Peach - Pink/peach YAG

Rutile - Man-made Rutile
Strontium Titanate - Man-made Strontium Titanate
Zincite - Man made Zincite in all color, green, yellow, red, orange

Return to Synthetics Index

E-mail to inquire or order: jeff@faceters.com