cubic Nesosilicates
Almandine (Combination)
Fe3Al2(SiO4)3
Crystal Structure
#! Species: Almandine
#! System: Cubic (m3m)
#! Habit: Dodecahedron-trapezohedron combination
cubic[m3m]:{110}@1.0 + {211}@0.5
cubic
m3m
{110} {211}
Quick Facts
Hardness
7.0
Specific Gravity
4.05
Refractive Index
1.78
Optical Character
Isotropic
Physical Properties
Crystal Systemcubic
Hardness (Mohs)7.0
Specific Gravity4.05
CleavageNone
FractureConchoidal to uneven
LustreVitreous to resinous
Optical Properties
Refractive Index1.78
Optical CharacterIsotropic
Dispersion0.024
PleochroismNone (isotropic)
Colours
Deep redBrownish-redPurplish-redDark red
Localities
IndiaSri LankaBrazilMadagascarUSA (Idaho)Mozambique
Common Inclusions
Rutile needles (silk)Rounded crystalsFingerprint inclusions
Known Treatments
None commonly applied
Crystal Forms
dodecahedrontrapezohedron
Related Minerals
Other minerals in the cubic system
