cubic Nesosilicates
Almandine (Combination)
Formula 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 System
- cubic
- Hardness (Mohs)
- 7.0
- Specific Gravity
- 4.05
- Cleavage
- None
- Fracture
- Conchoidal to uneven
- Lustre
- Vitreous to resinous
Optical Properties
- Refractive Index
- 1.78
- Optical Character
- Isotropic
- Dispersion
- 0.024
- Pleochroism
- None (isotropic)
Characteristics
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
