Formula: Ca2Pb3(AsO4)3Cl
Anhydrous phosphate containing halogen, hedyphane group, apatite supergroup
Specific gravity: 5.82
Hardness: 4½
Streak: White
Colour: White, yellow-white, bluish
Solubility: Soluble in nitric acid

Metamorphic environments
Hydrothermal environments

Hedyphane is a relatively rare secondary mineral found in metamorphosed manganese deposits.

At Långban, Värmland, Sweden (the type locality), hedyphane occurs filling fissures in a garnet-pyroxene matrix, associated with baryte, barylite, rhodonite, hausmannite, bixbyite, phlogopite, amphibole and calcite. Specimens have been found consisting of massive, calcite-bearing rock, coated with calcite crystals. These are, in turn, coated with hedyphane crystals, followed by sparse amounts of allactite and two generations of hausmannite.

At Pajsberg, Värmland, Sweden, hedyphane occurs with tephroite and calcite in magnetite.

At Franklin, New Jersey, USA, hedyphane is the most abundant non-silicate lead mineral, associated with barylite, calcite, willemite, native copper, native lead, hancockite, rhodonite, baryte, axinite-(Mn), apatite and cahnite in veinlets in a metamorphosed zinc orebody. In some specimens hedyphane is the chief mineral, forming the matrix for the other species; in others calcite encloses the other minerals. Specimens of hedyphane from the Parker Shaft, Franklin mine, contain hedyphane associated with axinite, grossular and hancockite.

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