Class : Silicates
    Subclass : Sorosilicates
    Crystal System : Tetragonal
    Chemistry : CaMgSiO₇
    Rarity : Rare

Akermanite is isomorphic to gehlenite, with which it forms a continuous series and whose deposits it often shares. It is the Swedish metallurgist Anders Âkerman who gave it its name. This calcium silicate is a carbonate rock mineral found in basic volcanic rocks rich in calcium, limestone and dolomites transformed by thermal metamorphism, and certain calcic alkaline rocks. Akermanite also crystallizes in abundance in foundry and incinerator furnaces and is therefore an essential constituent of metallurgical slag and incineration bottom ash. It occurs as short prismatic to thin tabular crystals, or in masses ; it is colorless, yellowish-gray, dark green to dark brown. Artificial crystals from foundries and incinerators have acicular to bacillary habits, very different from those of natural crystals. Photo © Stephan Wolfsried - Natural Akermanite from Caspar quarry xenoliths, Bellerberg, Germany

Twin are known on {100} and 001, sometimes cruciform.

No fake reported for this mineral species.