Specification :

Any of several minerals from which Lead is extracted. The primary ore is galena or Lead sulphite PbS. This is unstable, and on prolonged exposure to the atmosphere it oxidizes into the minerals cerussite PbCO3 and anglesite PbSO4. Lead ores are usually associated with other metals, particularly silver which can be mined at the same time – and zinc, which can cause problems during smelting.