Andradite (Rhombic Dodecahedron) crystal structure
cubic Nesosilicates

Andradite (Rhombic Dodecahedron)

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

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Physical Properties

Crystal Systemcubic
Hardness (Mohs)6.5
Specific Gravity3.82
CleavageNone
FractureConchoidal to uneven
LustreAdamantine to vitreous

Optical Properties

Refractive Index1.855
Optical CharacterIsotropic
Dispersion0.057
PleochroismNone (isotropic)

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