Demantoid

Real mineral · very rare · Ca₃Fe₂(SiO₄)₃

Green andradite garnet with the highest dispersion of any garnet, exceeding even diamond. Characteristic horsetail inclusions of chrysotile fibres are unique to specimens from the Ural Mountains. Named for its diamond-like fire.

Identity

Formula

Ca₃Fe₂(SiO₄)₃

Chemical class

silicate

Mineral group

Garnet, Grossular, Spessartine, Tsavorite, Uvarovite

Also known as

Green andradite garnet

Crystallography

Crystal system

cubic

Habits

dodecahedral, massive

Fracture

conchoidal

Physical properties

Mohs hardness

6.5

Density

3.84 g/cm³

Luster

adamantine, vitreous

Colors

green, yellow-green, olive green

Streak

white

Transparency

transparent

Geology

Origins

metamorphic

Host rocks

serpentinite, schist

Associated minerals

Serpentine, Calcite, Chlorite

Geography

Russia (Ural Mountains), Namibia, Iran, Italy

Classification

Rarity

very rare

Gem quality

Yes

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