Garnet – Andradite

Scientific Name: Melanite

Group: Silicates – neosilicates

Chemical composition: Ca3Fe2(SiO4)3

Colors: Black

Hardness: 6.5 to 7.5

Formation: Cubic crystals; Dodecahedral, trapezohedral form

Principal Sources: Ural and Chutosky Mountains, Russia; Valmalenco, Italy; California; Arizona

Special Notes: The garnet group includes a group of minerals that have been used since the Bronze Age as gemstones and abrasives. The name “garnet” may come from either the Middle English word gernet meaning ‘dark red’, or the Latin granatus (“grain”), possibly a reference to the Punica granatum (“pomegranate”), a plant with red seeds similar in shape, size, and color to some garnet crystals. Garnet occurs in metamorphic and igneous rocks worldwide. Andradite includes three varieties: Melanite: Black in color, referred to as “titanian andradite”; Demantoid: Vivid green in color, one of the most valuable and rare stones in the gemological world; and Topazolite: Yellow-green in color and sometimes of high enough quality to be cut into a faceted gemstone. Andradite was named after the Brazilian mineralogist JosĂ© Bonifácio de Andrade e Silva.