trigonal Synthetic synthetic corundum
Synthetic Sapphire (Verneuil) (Boule)
Formula Al2O3:Fe,Ti
Crystal Structure
#! Species: Synthetic Sapphire (Verneuil)
#! System: Trigonal (-3m)
#! Habit: Corundum habit from flame fusion boule
trigonal[-3m]:{10-10}@1.0 + {10-11}@0.7 | elongate(c:1.8)
trigonal
-3m
{10-10} {10-11}
Quick Facts
Hardness
9.0
Specific Gravity
3.99
Refractive Index
1.762
Optical Character
Uniaxial -
Physical Properties
- Crystal System
- trigonal
- Hardness (Mohs)
- 9.0
- Specific Gravity
- 3.99
- Cleavage
- None (parting on {0001} and {10-11})
- Fracture
- Conchoidal
- Lustre
- Vitreous to adamantine
Optical Properties
- Refractive Index
- 1.762
- Birefringence
- 0.008
- Optical Character
- Uniaxial -
- Dispersion
- 0.018
- Pleochroism
- strong: violetish-blue / greenish-blue
- Fluorescence
- Inert to weak (varies by colour)
Origin & Identification
- Origin
- Synthetic
- Growth Method
- Flame Fusion
- First Produced
- 1910
- Diagnostic Features
- Curved striae, spherical gas bubbles, uniform colour, no natural inclusions (silk, zoning)
Characteristics
Colours
BlueColourlessYellowGreenPink
Common Inclusions
Curved striaeGas bubblesUnmelted alumina
Natural Counterpart
The natural gem this synthetic imitates
Related Minerals
Other minerals in the trigonal system
