trigonal
Sapphire
Al2O3:Fe,Ti
Quick Facts
Hardness
9
Specific Gravity
3.99-4.01
Refractive Index
1.762-1.770
Crystal Structure
trigonal[-3m]:{10-10}@1.0 + {10-11}@0.7 | elongate(c:1.8) trigonal
-3m
{10-10} {10-11}
Physical Properties
Crystal Systemtrigonal
Hardness (Mohs)9
Specific Gravity3.99-4.01
CleavageNone (parting along twin planes)
FractureConchoidal to uneven
LustreVitreous to adamantine
Optical Properties
Refractive Index1.762-1.770
Birefringence0.008
PleochroismDistinct to strong (varies with colour)
Dispersion0.018
Interactive Preview
Open this crystal in the CDL Playground to rotate, export, and explore in 3D.
Open in Playground trigonal[-3m]:{10-10}@1.0 + {10-11}@0.7 | elongate(c:1.8) Related Minerals
Other minerals in the trigonal system