Galena, also calledlead glance, is the natural mineral form oflead(II) sulfide (PbS). It is the most importantore oflead and an important source ofsilver.[5]
As a pure specimen held in the hand, understandard temperature and pressure, galena is insoluble in water and so is almost non-toxic. Handling galena under these specific conditions (such as in a museum or as part of geology instruction) poses practically no risk; however, as lead(II) sulfide is reasonably reactive in a variety of environments, it can be highly toxic if swallowed or inhaled, particularly under prolonged or repeated exposure.[6]
In some deposits, the galena contains up to 0.5%silver, a byproduct that far surpasses the main lead ore in revenue.[10] In these deposits significant amounts of silver occur as includedsilver sulfide mineral phases or as limited silver insolid solution within the galena structure. Theseargentiferous galenas have long been an important ore of silver.[7][11] Silver-bearing galena is almost entirely of hydrothermal origin; galena in lead-zinc deposits contains little silver.[9]
Australia is the world's leading producer of lead as of 2021, most of which is extracted as galena. Argentiferous galena was accidentally discovered atGlen Osmond in 1841, and additional deposits were discovered nearBroken Hill in 1876 and atMount Isa in 1923.[13] Most galena in Australia is found in hydrothermal deposits emplaced around 1680 million years ago, which have since been heavily metamorphosed.[14]
The largest documented crystal of galena is composite cubo-octahedra from theGreat Laxey Mine,Isle of Man, measuring 25 cm × 25 cm × 25 cm (10 in × 10 in × 10 in).[15] This specimen is on permanent display in the minerals gallery of theNatural History Museum, London.
Galena belongs to theoctahedral sulfide group of minerals that have metalions in octahedral positions, such as the iron sulfidepyrrhotite and the nickel arsenideniccolite. The galena group is named after its most common member, with otherisometric members that includemanganese bearingalabandite andniningerite.[9][4]
One of the oldest uses of galena was to producekohl, an eye cosmetic now regarded as toxic due to the risk oflead poisoning.[24] InAncient Egypt, this was applied around the eyes to reduce the glare of the desert sun and to repel flies, which were a potential source of disease.[25]
Inpre-Columbian North America, galena was used byindigenous peoples as an ingredient in decorative paints and cosmetics, and widely traded throughout the eastern United States.[26] Traces of galena are frequently found at theMississippian city atKincaid Mounds in present-day Illinois.[27] The galena used at the site originated from deposits in southeastern and central Missouri and the Upper Mississippi Valley.[26]
Galena is the primary ore of lead, and is often mined for its silver content.[7] It is used as a source of lead inceramic glaze.[28]
Galena is asemiconductor with a smallband gap of about 0.4 eV, which found use in earlywireless communication systems. It was used as the crystal incrystal radio receivers, in which it was used as a point-contactdiode capable of rectifying alternating current todetect the radio signals. The galena crystal was used with a sharp wire, known as a "cat's whisker", in contact with it.[29]
In modern times, galena is primarily used to extract its constituent minerals. In addition to silver, it is the most important source of lead, for uses such as inlead-acid batteries.[10]
^abcdeAnthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C., eds. (1990). "Galena".Handbook of Mineralogy(PDF). Vol. 1. Chantilly, VA: Mineralogical Society of America.ISBN0962209708.
^Young, Courtney A.; Taylor, Patrick R.; Anderson, Corby G. (2008).Hydrometallurgy 2008: Proceedings of the Sixth International Symposium. SME.ISBN9780873352666.
^abcdeKlein, Cornelis; Hurlbut, Cornelius S. Jr. (1993).Manual of mineralogy (after James D. Dana) (21st ed.). New York: Wiley. pp. 354–356.ISBN047157452X.
^Calvo, Miguel (2003).Minerales y Minas de España. Vol. II. Sulfuros y sulfosales [Minerals and mines of Spain] (in Spanish). Spain: Museo de Ciencias Naturales de Alava. pp. 293–301.ISBN84-7821-543-3.
^"Lead".Geoscience Australia. Australian Government. 4 March 2018. Retrieved26 June 2021.
^Walters, Stephen; Bailey, Andrew (1998-12-01). "Geology and mineralization of the Cannington Ag-Pb-Zn deposit; an example of Broken Hill-type mineralization in the eastern succession, Mount Isa Inlier, Australia".Economic Geology.93 (8):1307–1329.Bibcode:1998EcGeo..93.1307W.doi:10.2113/gsecongeo.93.8.1307.
^"Toxic trends".Wellcome Collection. 17 December 2019. Retrieved29 March 2024.
^Metropolitan Museum of Art (2005).The Art of Medicine in Ancient Egypt. New York. p. 10.ISBN1-58839-170-1.{{cite book}}: CS1 maint: location missing publisher (link)
