Note: Do not rely on this information. It is very old.
Cerussite
Cerussite, an important ore of lead, consisting of the carbonate of this metal, PbC03. It occurs in rhombic crystals, varying in colour from white to greyish-black. It is brittle, and has a sp. gr. 6.4, and is sometimes associated with the chloride of lead, and is then known as horn lead. It occurs in various localities in the United States, in Siberia, Hungary, Bohemia, the Harz, at Leadhills in Scotland, Wicklow in Ireland, and Cornwall and Derbyshire in England.