Andradite

Introduction: Andradite was first described by the Brazilian geologist, Jose Bonifacio d'Andrada e Silva. It is often found as dark red dodecahedral crystals. It is most common in metamorphic marble and calc-silicate rocks.

Distribution: Brown to black andradite garnet is found in the Otjosondu manganese deposit north of Okahandja. It also occurs in marble 60km east of Swakopmund and in some pegmatites including Davib West 62, Tsawisis 16 and Davib Ost 61. Farms Tubussis 22 and Tumib 20, west of Erongo also contains andradite.

Composition: Silicate

Crystal system: Cubic

Lustre: Resinous, vitreous

Streak: White

Hardness: 3.7-4.1