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Chemical Formula | PbS | ||||||||||
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Composition | Lead sulfide. May contain impurities, such as silver, arsenic, antimony, and copper. | ||||||||||
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Variable Formula | (Pb,Ag,As,Sb,Cu)S | ||||||||||
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Color | Steel-gray | ||||||||||
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Streak | Steel-gray | ||||||||||
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Hardness | 2½ - 3 | ||||||||||
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Crystal Forms and Aggregates |
(Isometric) Crystals, which may be cube, octahedrons, or a combination of the two frequently occur. Dodecahedrons are far less common. Also occurs massive, grainy, fibrous, platy, and as veins. | ||||||||||
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Transparency | Opaque | ||||||||||
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Specific Gravity | 7.4 - 7.6 (Pure = 7.57) | ||||||||||
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Luster | Metallic. Turns somewhat dull after exposure to air. | ||||||||||
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Cleavage | 1,3 - Cubic. May exhibit parting on octahedrons. | ||||||||||
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Fracture | Subconchoidal | ||||||||||
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Tenacity | Brittle | ||||||||||
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Other Names |  Galenite, Lead
Glance |
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Varieties | Acerila - Term used in a
few South American countries describing granular Galena. Argentiferous
Galena - Galena with a large silver content.
Formula = (Pb,Ag)S |
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In Group | Sulfides ; Simple sulfides | ||||||||||
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All About | Galena forms many interesting crystal
shapes. Some cubic crystals have their edges cut by the
partial octahedral growth, some octahedral crystals have their
points flattened by cubic growth, and many crystals are
found somewhat in-between cubic and octahedral. Dodecahedral growths may partially be found in
octahedral or cubic-octahedral crystals, resulting in
bizarre and interesting shapes. Galena specimens must be taken care of very well. They are easily damaged, and well formed crystals may shatter into small crystal fragments if put under slight pressure. Galena is a primary mineral. Most of the lead minerals, such as Cerrusite and Anglesite are secondary mineral formed from Galena. Impurities in the structure of Galena, such as silver and bismuth, may change Galena's cleavage properties. Galena containing bismuth may exhibit octahedral cleavage, and silver in Galena may cause a specimen to exhibit flaky, slightly bent cleavage fragments. Galena specimens tarnish when exposed to air becoming dull in luster. Freshly cleaved specimens exhibit a strong metallic luster, but over time the luster turns more dull, although still metallic. The tarnish can be temporarily removed by scrubbing the specimen with water and mild soap. |
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Uses | Galena is by far the greatest ore
of lead. Galena is the most common mineral containing
lead, and contains mostly lead. Since the extraction process is so simple, lead has been
extracted from Galena since the earliest times. Galena
was also used in early radio devices. Well crystallized
Galena specimens are popular collectors items. Galena from certain regions is rich in silver. Specimens may contain as much as 20 percent silver. Because of this, silver-rich Galena is commonly an ore of silver. |
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Striking Features | Steel-gray color, extreme heaviness, and fine cleavage | ||||||||||
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Popularity (1-4) | 1 | ||||||||||
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Prevalence (1-3) | 1 | ||||||||||
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Demand (1-3) | 1 | ||||||||||
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Distinguishing Similar Minerals |
Sphalerite - lacks cubic cleavage, lighter
(3.9 - 4.1), different streak (light brown to nearly
white) Stibnite - lacks fine cleavage, different crystal form Acanthite/Argentite - softer (2), is sectile Jamesonite - lacks fine cleavage, slightly lighter in weight (5.5 - 6.0), different crystal form Chalcocite - different crystal form, darker, lighter in weight (5.5 - 5.8) Tetrahedrite - harder (3 - 4), darker color, lighter in weight (4.6 - 5.1) |
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Commonly Occurs With |
Quartz, Sphalerite, Chalcopyrite, Pyrite, Bornite, Barite, Siderite, Dolomite, Calcite, Marcasite, Fluorite | ||||||||||
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Noteworthy Localities |
Galena is a very common mineral and occurs
in numerous localities. The localities mentioned here are
but a few of the prestigious ones. It occurs in numerous localities in England; the finest occur in Alston Moor and Weardale together with beautiful Fluorite. Many fine specimens also come from Germany, from many places in the Black Forest and Siegerland, as well as in Neudorf in the Harz Mountains. Other occurrences are in numerous places in Scotland, Italy, and Greenland, as well as France, Spain, Switzerland, and former Yugoslavia. Many interestingly formed crystals, such as twinned octahedrons and plates were found in Naica, Chihuahua, Mexico. In the U.S., the tri-state mining district, (the area around the conjunction of Kansas, Missouri, and Oklahoma), has produced perhaps the finest crystals. Enormous and well shaped crystals occur in that area together with Sphalerite, Dolomite, and Marcasite. Some of these famous areas localities include the Joplin area, Jasper Co., Missouri; Galena, Treece, and Baxter Springs, Cherokee Co., Kansas; and Picher, Ottawa Co., Oklahoma. Excellent Galena specimens have also come from the Sweetwater Mine, Reynolds Co., Missouri. Colorado has also produced fine specimens, notably in Leadville, Lake Co.; Central City, Georgetown, and Empire, Gilpin Co. The Coeur d'Alene District in Idaho is a very important lead deposit, containing rich amounts of Galena, sometimes argentiferous. In California, much Galena occurs at Darwin, Inyo Co., in the Blue Bell mine, San Bernardino Co., and in the Jamestown mine, Tuolumne Co. Large amounts of Galena are mined industrially mined in south-central and southwestern Wisconsin, where it goes towards the production of lead. |
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Picture Icon Links |
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Picture Links | 1. Hunk of cubic Galena 2. Galena in Calcite 3. Octagedral crystal 4. Massive Argentiferous Galena 5. Galena Octacube |
