Cahnite

Formula: Ca2B(AsO4)(OH)4
Compound arsenate
Specific gravity: 3.156
Hardness: 3
Streak: White
Colour: Colorless to white, also golden brown; colourless in transmitted light.
Solubility: Readily soluble in dilute hydrochloric acid
Environments:

Pegmatites
Metamorphic environments

Cahnite is a rare arsenate.

At Capo di Bove, Italy, cahnite occurs with zeolites in leucitic lava associated with phillipsite, chabazite and calcite.

At the Kombat mine, Namibia, cahnite is associated with natronambulite, gypsum, baryte and calcite.

In Siberia, Russia, cahnite is associated with svabite, magnetite, sphalerite, garnet and calcite.

At the type locality, the Franklin Mine, New Jersey, USA, cahnite is a late-stage mineral in pegmatites cutting a metamorphosed stratiform zinc orebody, associated with hedyphane, friedelite, pyrochroite, franklinite, willemite, rhodonite, datolite, axinite, jarosewichite, samfowlerite, flinkite, hodgkinsonite, hetaerolite, hausmannite, groutite, kentrolite, garnet and baryte.