Galena Galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide. It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms. It is often associated with the minerals sphalerite, calcite and fluorite. Galena is the main ore of lead, used since ancient times. Because of its somewhat low melting point, it was easy to liberate by smelting. It typically forms in low-temperature sedimentary deposits. In some deposits galena contains about
Mineral Rock forming minerals – typically silicates or occasionally carbonates – have a specific gravity of 2.5–3.5. High specific gravity is a diagnostic property of a mineral. A variation in chemistry (and consequently, mineral class) correlates to a change in specific gravity. Among more common minerals, oxides and sulfides tend to have a higher specific gravity as they include elements with higher atomic mass. A generalization is that minerals with metallic or adamantine lustre tend to have higher specific gravities than those having a non-metallic to dull lustre. For example, hematite, FeO, has a specific gravity of 5.26 while galena, PbS,