cubic Nesosilicates
Andradite (Rhombic Dodecahedron)
Formula Ca3Fe2(SiO4)3
Crystal Structure
#! Species: Andradite
#! System: Cubic (m3m)
#! Habit: Dodecahedron with trapezohedron
cubic[m3m]:{110}@1.0 + {211}@0.7
cubic
m3m
{110} {211}
Quick Facts
Hardness
6.5
Specific Gravity
3.82
Refractive Index
1.855
Optical Character
Isotropic
Physical Properties
- Crystal System
- cubic
- Hardness (Mohs)
- 6.5
- Specific Gravity
- 3.82
- Cleavage
- None
- Fracture
- Conchoidal to uneven
- Lustre
- Adamantine to vitreous
Optical Properties
- Refractive Index
- 1.855
- Optical Character
- Isotropic
- Dispersion
- 0.057
- Pleochroism
- None (isotropic)
Characteristics
Colours
Green (demantoid)Yellow-green (topazolite)Black (melanite)Brown
Localities
Russia (Urals)NamibiaMadagascarIranItaly
Common Inclusions
Horsetail (chrysotile) in demantoidCrystal inclusions
Known Treatments
None commonly applied
Crystal Forms
dodecahedrontrapezohedron
Diagnostic Features
Highest dispersion of any garnet (0.057); adamantine lustre; very high RI
Related Minerals
Other minerals in the cubic system
