trigonal
Amethyst
SiO2:Fe
Quick Facts
Hardness
7.0
Specific Gravity
2.65
Refractive Index
1.544
Crystal Structure
trigonal[32]:{10-10}@0.5 + {10-11}@1.2 + {01-11}@1.0 | elongate(c:2.0) trigonal
32
{10-10} {10-11} {01-11}
Physical Properties
Crystal Systemtrigonal
Hardness (Mohs)7.0
Specific Gravity2.65
CleavageNone
FractureConchoidal
LustreVitreous
Optical Properties
Refractive Index1.544
Birefringence0.009
PleochroismWeak (purple, grey-purple)
Dispersion0.013
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Open in Playground trigonal[32]:{10-10}@0.5 + {10-11}@1.2 + {01-11}@1.0 | elongate(c:2.0) Related Minerals
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