Gahnite, ZnAl₂O₄, is a rare mineral belonging to the

spinel Spinel () is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula in the cubic crystal system. Its name comes from the Latin word , which means ''spine'' in reference to its pointed crystals. Properties S ...

group. It forms octahedral crystals which may be green, blue, yellow, brown or grey. It often forms as an alteration product of

sphalerite Sphalerite (sometimes spelled sphaelerite) is a sulfide mineral with the chemical formula . It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in sedimentary exhalative, Mississippi-V ...

in altered massive sulphide deposits such as at

Broken Hill Broken Hill is an inland mining city in the far west of outback New South Wales, Australia. It is near the border with South Australia on the crossing of the Barrier Highway (A32) and the Silver City Highway (B79), in the Barrier Range. It i ...

, Australia. Other occurrences include

Falun Falun () is a city and the seat of Falun Municipality in Dalarna County, Sweden, with 37,291 inhabitants in 2010. It is also the capital of Dalarna County. Falun forms, together with Borlänge, a metropolitan area with just over 100,000 inhabita ...

Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...

where it is found in

pegmatites A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic com ...

and

skarn Skarns or tactites are hard, coarse-grained metamorphic rocks that form by a process called metasomatism. Skarns tend to be rich in calcium-magnesium-iron-manganese-aluminium silicate minerals, which are also referred to as calc-silicate minerals ...

s; and, in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territo ...

Charlemont, Massachusetts Charlemont is a town in Franklin County, Massachusetts, United States. The population was 1,185 at the 2020 census. It is part of the Springfield, Massachusetts Metropolitan Statistical Area. History Charlemont was first colonized by Moses R ...

;

Spruce Pine, North Carolina Spruce Pine is a town in Mitchell County, North Carolina, United States. The population was 2,175 at the 2010 census. History Spruce Pine was founded in 1907 when the Clinchfield Railroad made its way up the North Toe River from Erwin, Tennesse ...

;

White Picacho district, Arizona White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White on ...

;

Topsham, Maine Topsham () is a town in Sagadahoc County, Maine, United States. The population was 9,560 at the 2020 census. It is part of the Portland– South Portland– Biddeford, Maine metropolitan statistical area. The town is home to the annual Topsh ...

; and

Franklin, New Jersey Franklin is a borough in Sussex County, in the U.S. state of New Jersey. As of the 2010 United States Census, the borough's population was 5,045 Johan Gottlieb Gahn Johan Gottlieb Gahn (19 August 1745 – 8 December 1818) was a Swedish chemist and metallurgist who isolated manganese in 1774. Gahn studied in Uppsala 1762 – 1770 and became acquainted with chemists Torbern Bergman and Carl Wilhelm Scheele. ...

(1745–1818), the discoverer of the element

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy u ...

. It is sometimes called ''zinc spinel''.

References

Zinc minerals Aluminium minerals Spinel group Cubic minerals Minerals in space group 227 Minerals described in 1807 {{Oxide-mineral-stub

See also

References