Images
Formula: KAl(SO4)2.12H2O
Hydrated normal sulphate, alum group
Specific gravity: 1.757
Hardness: 2
Streak: White
Colour: Colourless, white, colourless in transmitted light
Solubility: Soluble in water
Environments
Hydrothermal environments
Fumeroles
Alum-(K) is formed from argillaceous rocks or coal containing oxidising
pyrite or marcasite; it may be a
fumarolic or solfataric precipitate. Associated minrals include alunogen,
pickeringite, epsomite,
melanterite, gypsum and
sulphur
(HOM).
Localities
The type locality is Solfatara di Pozzuoli, Pozzuoli, Naples, Campania, Italy.
Back to Minerals