Georgerobinsonite, named for George Willard Robinson, is a

lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

chromate Chromate or chromat, and their derived terms, may refer to: Chemistry * Chromate and dichromate, ions * Monochromate, an ion * Trichromate, an ion * Tetrachromate, an ion * Chromate conversion coating, a method for passivating metals Biolog ...

mineral with

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...

Pb₄(CrO₄)₂(OH)₂FCl. It exhibits very small, transparent crystals with a bright orange-red color. It was obtained from the Mammoth–St. Anthony Mine in Arizona in the 1940s and identified in 2009.

History

The

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

for georgerobinsonite was found in the Mammoth–St. Anthony Mine in

Tiger, Arizona Tiger is a Unincorporated area, former populated place in Pinal County, Arizona, Pinal County in the U.S. state of Arizona. The town was settled as Schultz ''circa'' 1881 in what was then the Arizona Territory, then later reestablished as Tige ...

. The sample was collected by Dan Mayers in 1943 or 1944. At this time, the mine was operating at a level where a number of exotic minerals have been discovered.Cooper, p. 866. The exact location of its origin is unknown, but it is likely from the Collins vein at the 500 level.Cooper, p. 867. The sample, labelled M 117 by Mayers, was donated along with many others to the Department of Mineralogy at

Harvard Harvard University is a private Ivy League research university in Cambridge, Massachusetts, United States. Founded in 1636 and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher lear ...

. Professor Heinrich Meixner obtained it in the 1950s in an exchange with the curator of Harvard's mineral collection, Professor C. Frondel.Cooper, pp. 866–67. Werner H. Paar then acquired it in the early 1970s. Several years prior to 2011, reexamination of M 117 revealed very small crystals of an orange-red mineral. They were initially misidentified as

wulfenite Wulfenite is a lead molybdate mineral with the formula Pb Mo O4. It often occurs as thin tabular crystals with a bright orange-red to yellow-orange color, sometimes brown, although the color can be highly variable. In its yellow form it is some ...

, but later determined to be a new mineral species. In November 2009, the Commission on New Minerals, Nomenclature and Classification of the

International Mineralogical Association Founded in 1958, the International Mineralogical Association (IMA) is an international group of 40 national societies. The goal is to promote the science of mineralogy and to standardize the nomenclature of the 5000 plus known mineral species. ...

(IMA) designated the mineral as IMA 2009-068. The IMA later approved georgerobinsonite as the recommended name. Georgerobinsonite is named for George Willard Robinson, A. E. Seaman Mineral Museum curator since 1996 and mineralogy professor at

Michigan Technological University Michigan Technological University (Michigan Tech, MTU, or simply Tech) is a public research university in Houghton, Michigan, United States. It was founded in 1885 as the Michigan Mining School, the first post-secondary institution in the Uppe ...

Properties

Georgerobinsonite is a soft, brittle mineral that forms crystals less than across. The mineral possesses a pale-orange streak and an

adamantine luster Lustre (Commonwealth English) or luster (American English; see spelling differences) is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the Latin ''lux'', meaning "light", and generall ...

. It is most strongly associated with

cerussite Cerussite (also known as lead carbonate or white lead ore) is a mineral consisting of lead carbonate with the chemical formula PbCO3, and is an important ore of lead. The name is from the Latin ''cerussa'', white lead. ''Cerussa nativa'' was ...

and

diaboleite Diaboleite is a blue-colored mineral with formula Pb2CuCl2(OH)4. It was discovered in England in 1923 and named ''diaboleite'', from the Greek word διά and boleite, meaning "distinct from boleite". The mineral has since been found in a number ...

References

Bibliography

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External links

Photos from mindat.org
Lead minerals Chromate minerals Orthorhombic minerals Minerals in space group 59