Detailed close-up of a spessartine crystal from Pakistan — Photo: ButtShark · CC0
Spessartine
Also known as: Spessartite, Mandarin garnet.
The orange-red manganese-aluminium garnet — named for the Spessart district of Bavaria.
Intro adapted from Wikipedia (CC BY-SA).
Spessartine is an IMA-recognized mineral species in the silicate class, with the chemical formula Mn²⁺₃Al₂(SiO₄)₃.
It crystallizes in the cubic crystal system (space group Ia3d). It is a member of the Garnet structural group.
Key properties: Mohs hardness 7–7.5; specific gravity 4.19; typically orange or red or brown or yellow; White streak; Vitreous luster; refractive index 1.8; optically isotropic.
IMA symbol Sps, grandfathered status — known before the IMA’s founding, named in 1832.
Common in granite pegmatites, granites, and rhyolites. Formed in some skarns and metasomatic manganese-rich rocks adjacent to igneous intrusions or in regionally metasomatized areas.
It is found associated with Quartz, potassic feldspar, tourmaline, rhodonite, pyroxmangite, tephroite, alleghanyite, galaxite, muscovite, topaz, apatite, beryl, albite, bixbyite.
The name is derived from the locality near Spessart, Germany.
Collections: Gemstones, Collector Favorites.