- Litharge
Litharge is one of the natural mineral forms of
lead(II) oxide , PbO. Litharge is a secondary mineral which forms from theoxidation ofgalena ore s. It forms as coatings and encrustations with internal tetragonal crystal structure. It is dimorphous with the orthorhombic formmassicot . It forms soft (Mohs hardness of 2), red, greasy-appearing crusts with a very highspecific gravity of 9.14–9.35.It was first described as a mineral in 1917 for an occurrence in
San Bernardino County, California .Historically, the term "litharge" has been combined to refer to other similar substances. For example, "litharge of gold" is litharge mixed with
red lead , giving it a red color; "litharge of silver" is litharge that comes as a by-product of separating silver from lead; "litharge of bismuth" is a similar result of the oxidation of bismuth. The term has also been used as a synonym forwhite lead or red lead.OED|litharge]References
* Palache, C., H. Berman, and C. Frondel (1944) Dana’s system of mineralogy, (7th edition), v. I, 514–515
* [http://www.webmineral.com/data/Litharge.shtml Webmineral data]
* [http://www.mindat.org/min-2466.html Mindat with location data]
* [http://rruff.geo.arizona.edu/doclib/hom/litharge.pdf Mineral Data Publishing - PDF]
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