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 -
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Open in PlaygroundPhysical 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
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Open in PlaygroundNatural Counterpart
The natural gem this synthetic imitates
Related Minerals
Other minerals in the trigonal system
