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. It is a bluish, grey, or black mineral of metallic appearance, consisting of lead sulphide. It is the chief ore of lead.
It 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.
General Information
- Category: Sulfide mineral, octahedral subgroup
- Formula: PbS
- Crystal system: Cubic
- Crystal class: Hexoctahedral (m3m)
Fig: Galena
Properties
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.
- Color: Lead gray and silvery
- Twinning: Contact, penetration and lamellar
- Fracture: Subconchoidal
- Tenacity: Brittle
- Mohs scale hardness: 2.5–2.75
- Luster: Metallic on cleavage planes
- Streak: Lead gray
- Diaphaneity: Opaque
- Specific gravity: 7.2–7.6
- Optical properties: Isotropic and opaque
Occurrence
Galena deposits are found worldwide in various environments. Noted deposits include those at Freiberg in Saxony; Cornwall, the Mendips in Somerset, Derbyshire, and Cumberland in England; the Madan, Rhodope Mountains in Bulgaria; the Sullivan Mine of British Columbia; Broken Hill and Mount Isa in Australia; and the ancient mines of Sardinia.
Galena also occurs in North African countries and at Mount Hermon in Northern Israel. In the United States, it occurs most notably in the Mississippi Valley-type deposits of the Lead Belt in southeastern Missouri, and in the Driftless Area of Illinois, Iowa, and Wisconsin.
Uses
Galena is the primary ore of lead, which is mainly used in making lead-acid batteries; however, significant amounts are also used to make lead sheeting and lead shot. Galena is often mined for its silver content, such as at the Galena Mine in northern Idaho.
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