Richterite is a

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ...

silicate

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ...

belonging to the

amphibole Amphibole () is a group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Its IMA symbol is ...

group. If

iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in ...

replaces the

within the structure of the mineral, it is called ferrorichterite; if fluorine replaces the

hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydrox ...

, it is called

fluororichterite Fluororichterite is a rare amphibole with formula Na(NaCa)Mg5Si8O22F2. Occurrence Fluororichterite was first reported from the Ilmen Nature Reserve, Ilmen Mountains, Chelyabinsk Oblast', Southern Urals, Russia. It was recognized by the Internatio ...

. Richterite crystals are long and prismatic, or prismatic to fibrous

aggregate Aggregate or aggregates may refer to: Computing and mathematics * collection of objects that are bound together by a root entity, otherwise known as an aggregate root. The aggregate root guarantees the consistency of changes being made within the ...

, or rock-bound crystals. Colors of richterite range from brown, grayish-brown, yellow, brownish- to rose-red, or pale to dark green. Richterite occurs in thermally metamorphosed

limestones Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when t ...

in contact

metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, cau ...

zones. It also occurs as a

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

product in mafic

igneous Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma o ...

rocks, and in manganese-rich ore deposits. Localities include Mont-Saint-Hilaire, Quebec, and Wilberforce and

Tory Hill, Ontario A Tory () is a person who holds a political philosophy known as Toryism, based on a British version of traditionalism and conservatism, which upholds the supremacy of social order as it has evolved in the English culture throughout history. The ...

, Canada; Långban and Pajsberg, Sweden;

West Kimberley West Kimberley is a sub region of the Kimberley region of Western Australia. The region is defined according to different purposes. The area has been listed as a heritage area. Related to the heritage listing, the area has had portions that have ...

, Western Australia; Sanka, Myanmar; and, in the US, at Iron Hill, Colorado; Leucite Hills, Wyoming; and

Libby, Montana Libby is a city in northwestern Montana, United States and the county seat of Lincoln County. The population was 2,775 at the 2020 census. Libby suffered from the area's contamination from nearby vermiculite mines contaminated with particularl ...

. The mineral was named in 1865 for the German mineralogist Hieronymous Theodor Richter (1824–1898).

References

{{Reflist * Bonewitz, 2008, ''Smithsonian Rock and Gem'' Sodium minerals Calcium minerals Magnesium minerals Amphibole group Monoclinic minerals Minerals in space group 12