trigonal Synthetic synthetic corundum
Synthetic Sapphire (Verneuil) (Boule)
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 Systemtrigonal
Hardness (Mohs)9.0
Specific Gravity3.99
CleavageNone (parting on {0001} and {10-11})
FractureConchoidal
LustreVitreous to adamantine
Optical Properties
Refractive Index1.762
Birefringence0.008
Optical CharacterUniaxial -
Dispersion0.018
Pleochroismstrong: violetish-blue / greenish-blue
FluorescenceInert to weak (varies by colour)
Origin & Identification
OriginSynthetic
Growth MethodFlame Fusion
First Produced1910
Diagnostic FeaturesCurved striae, spherical gas bubbles, uniform colour, no natural inclusions (silk, zoning)
Colours
BlueColourlessYellowGreenPink
Common Inclusions
Curved striaeGas bubblesUnmelted alumina
Natural Counterpart
The natural gem this synthetic imitates
Related Minerals
Other minerals in the trigonal system
