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Search Mineralpedia – A Mineral Photo Database and Identification Guide


Named after the type locality at Mina Ojuela near Mapimi in Durango, Mexico. Additional localities for Ojuelaite include at the Sterling mine in New Jersey, USA, at Laurion in Greece, and at the Tsumeb mine in Tsumeb, Namibia. Ojuelaite forms in oxidized arsenic-rich polymetallic hydrothermal ore deposits. Assocaited minerals include paradamite, scorodite, smithsonite, limonite, tennantite, and goethite.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/ojuelaite.pdf


Named after its common appearance as a mineral that is olive-green in color. Most typically olive green, but also brownish green to yellow green. Short prismatic to acicular crystals, also fibrous (variety leucochalcite), to tabular. It is “the most common secondary copper arsenate in the oxidized zone of hydothermal copper deposits.” Most notable localitiies include Majuba Hill, Nevada; Tsumeb; Tintic district, Utah; Cornwall, England. Other localities include France, Germany, Greece, Morocco, Namibia, and Chile among many others. 

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/olivenite.pdf


Named after Frank Olmstead and first found at the Hesnard mine and later the Big Chief mine, and White Cap mines. All three are zoned pegmatites near Keystone. Olmsteadite was the first secondary transition-metal phosphate containg niobium indicating a paragenetic relationship between Columbite-Tantalite and a phosphate, probably Triphylite. Occurs as thick prismatic, very lustrous, sub-adamantine, deep red-brown, well-developed crystals to 1mm. (Moore, PB et al AM v.61, (1976). South Dakota School of Mines display specimen contain crystals to about 10mm. Can be confused with deep red Sphalerite or dark smoky Quartz, both of which are found in the same matrix of advanced altered phosphate rock with cores of Siderite and Hydroxylapatite.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/olmsteadite.pdf


Named in honor of Juan Augusto Olsacher, a former Professor of Mineralogy at Cordoba University in Cordoba, Argentina who studied selenium-rich minerals in Argentina. Olascherite is a rare mineral found in Bolivia, Argentina, and Italy among only a few others. It occurs as a secondary mineral in oxidized selenium-rich hydrothermal deposits. Olascherite is pyroelectric.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/olsacherite.pdf

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