hydrocerussite

Hydrocerussite is a lead carbonate mineral with the chemical formula Pb3(CO3)2(OH)2. It is a basic lead carbonate and is commonly associated with cerussite (PbCO3), with which it forms in oxidized zones of lead-bearing ore deposits. It can occur as a secondary alteration product of galena or cerussite and is frequently found in veins, crusts, and aggregates.

Physical properties: Hydrocerussite typically presents as colorless to white, gray, or pale brown crystals and masses; crystals are usually tabular or prismatic and form bladed to prismatic habits. It has a vitreous to pearly luster, a hardness of about 3.5–4 on the Mohs scale, and a high specific gravity of roughly 6.3–6.6. It is a relatively soft mineral and will effervesce slowly in dilute acids due to its carbonate content.

Occurrence and locality: It has a worldwide distribution in oxidized zones of lead ore deposits and is commonly found together with cerussite, anglesite, and other secondary lead minerals. Notable localities include various historic mining districts; exact localities are well documented by mineralogical literature.

Etymology and naming: The name reflects its relation to cerussite and its hydroxy component.

Uses and significance: Hydrocerussite is of interest mainly to mineral collectors and researchers. It can be an indicator of late-stage oxidation in lead deposits and helps in understanding secondary mineralization processes. Handling should consider lead content; it is not used as a primary ore.