thumb|Andradite garnet – Jiangxi, Nantan, China.
Andradite is a mineral species of the garnet group. It is a nesosilicate, with chemical formula Ca<sub>3</sub>Fe<sub>2</sub>Si<sub>3</sub>O<sub>12</sub>.
Andradite includes four varieties:
- Colophonite: a historical variety found in the Scandinavian islands, brownish or reddish in color, often opaque or translucent.
- Demantoid: Vivid green in color, one of the most valuable and rare stones in the gemological world.
- Melanite: Black in color due to limited substitution of titanium for iron. Also known as "titanian andradite". Forms a solid solution with morimotoite and schorlomite depending on titanium and iron content.
- Topazolite: Yellow-green in color and sometimes of high enough quality to be cut into a faceted gemstone, it is rarer than demantoid.
The spin structure of andradite contains two mutually canted equivalent antiferromagnetic sublattices below the Néel temperature (T<sub>N</sub> = 11 K).
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File:Mélanite-Mali.jpg|Black crystals of andradite: melanite
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See also
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- Almandine
- Geology
- Grossular
- Mineral
- Mineral collecting
- Pyrope
- Spessartine
- Tsavorite
- Uvarovite