Formula: Pb2Cl3(OH)
Specific gravity: 5.82 to 6.61
Hardness: 3 to 4
Streak: White
Colour: Colourless, white, yellowish or bluish tints
Solubility: Soluble in dilute nitric acid, decomposed by water, rendering a yellow-white precipitate of lead oxychloride

Hydrothermal environments

Penfieldite is a secondary mineral derived from smelting activities and sea water contact (Webmin).


At the Margarita Mine, Caracoles, Sierra Gorda, Antofagasta Province, Antofagasta, Chile, penfieldite occurs in an oxidised hydrothermal lead deposit (HOM)

At the type locality, Lavrion slag localities, Lavreotiki, East Attica, Attica, Greece, penfieldite occurs as an alteration product of lead-bearing slag immersed in seawater, associated with paralaurionite and phosgenite (Mindat, HOM).

At the Baratti slag locality, Piombino, Livorno Province, Tuscany, Italy, penfieldite is associated with fiedlerite and cotunnite (HOM).

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