Galena

Galena, or LEAD-GLANCE, a mineral which is essentially a sulphide of lead, the proportions being 13·4 sulphur and 86·6 lead; but usually containing a little silver, and sometimes copper, iron, zinc, antimony, or selenium. It has a hardness equal to 2½–3, and a specific gravity of 7·2–7·6. It is of a lead-gray colour, with a metallic lustre, is found massive, or sometimes granular, or crystallised in cubes or octahedrons. It is very easily broken, and its fragments are cubical. It occurs in veins, beds, and imbedded masses, often accompanying other metallic ores, such as zinc-blende, in the older stratified rocks, but most of all in what is known as the carboniferous or mountain-limestone. It is found very abundantly in some parts of Britain, and in many other countries, as in Sweden, Germany, Switzerland, Hungary, France, the United States, &c. Almost all the lead of commerce is obtained from it. It sometimes contains so much silver that the separation of that metal is profitably carried on. The Lead (q.v.) is extracted from it by a very simple process.