Benstonite is a
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. ( ...
with formula Ba
6Ca
6Mg(CO
3)
13.
[ Discovered in 1954, the mineral was described in 1961 and named after Orlando J. Benston (1901–1966).
]
Description and occurrence
Benstonite is translucent and white, pale yellow, or pale yellow-brown in color.[ The mineral occurs as cleavable masses; cleavage fragments are nearly perfectly ]rhombohedral
In geometry, a rhombohedron (also called a rhombic hexahedron or, inaccurately, a rhomboid) is a three-dimensional figure with six faces which are rhombus, rhombi. It is a special case of a parallelepiped where all edges are the same length. It c ...
in shape. Cleavage faces are up to across and slightly curved. On large specimens, the faces exhibit a mosaic structure similar to that in some specimens of dolomite Dolomite may refer to:
*Dolomite (mineral), a carbonate mineral
*Dolomite (rock), also known as dolostone, a sedimentary carbonate rock
*Dolomite, Alabama, United States, an unincorporated community
*Dolomite, California, United States, an unincor ...
and siderite
Siderite is a mineral composed of iron(II) carbonate (FeCO3). It takes its name from the Greek word σίδηρος ''sideros,'' "iron". It is a valuable iron mineral, since it is 48% iron and contains no sulfur or phosphorus. Zinc, magnesium and ...
. Benstonite fluoresce
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, tha ...
s red or yellow under x-rays and longwave and shortwave ultraviolet. The mineral also exhibits strong red phosphorescence
Phosphorescence is a type of photoluminescence related to fluorescence. When exposed to light (radiation) of a shorter wavelength, a phosphorescent substance will glow, absorbing the light and reemitting it at a longer wavelength. Unlike fluo ...
.[
Benstonite is known to occur in Canada, China, India, Italy, Namibia, Russia, Sweden, and the United States.][ It occurs in association with ]alstonite
Alstonite, also known as bromlite, is a low temperature hydrothermal mineral that is a rare double carbonate of calcium and barium with the formula , sometimes with some strontium. Barytocalcite and paralstonite have the same formula but different ...
, barite
Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate ( Ba S O4). Baryte is generally white or colorless, and is the main source of the element barium. The ''baryte group'' consists of baryte, celestine (strontium sulfate), ...
, barytocalcite
Barytocalcite is an anhydrous barium calcium carbonate mineral with the chemical formula Ba Ca( C O3)2. It is trimorphous with alstonite and paralstonite, that is to say the three minerals have the same formula but different structures. Baryte a ...
, calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...
, daqingshanite, fluorite
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon.
The Mohs sca ...
, huntite
Huntite is a carbonate mineral with the chemical formula Mg3Ca(CO3)4. Huntite crystallizes in the trigonal system and typically occurs as platy crystals and powdery masses. For most of recorded history its main use was as a white pigment. Today ...
, monazite
Monazite is a primarily reddish-brown phosphate mineral that contains rare-earth elements. Due to variability in composition, monazite is considered a group of minerals. The most common species of the group is monazite-(Ce), that is, the cerium- ...
, phlogopite
Phlogopite is a yellow, greenish, or reddish-brown member of the mica family of phyllosilicates. It is also known as magnesium mica.
Phlogopite is the magnesium endmember of the biotite solid solution series, with the chemical formula KMg3AlSi3O ...
, pyrite
The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral.
Pyrite's metallic Luster (mineralogy), lust ...
, 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 deposits, sedimen ...
, strontianite
Strontianite ( Sr C O3) is an important raw material for the extraction of strontium. It is a rare carbonate mineral and one of only a few strontium minerals. It is a member of the aragonite group.
Aragonite group members: aragonite (CaCO3), ...
, and quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...
.[
]
Synthesis
The mineral was first synthesized in 1973 during a study of the Ba-Mg-Ca-CO3 system in aqueous solution. At room temperature, a solution containing proportional quantities of magnesium chloride
Magnesium chloride is the family of inorganic compounds with the formula , where x can range from 0 to 12. These salts are colorless or white solids that are highly soluble in water. These compounds and their solutions, both of which occur in natu ...
, barium chloride
Barium chloride is an inorganic compound with the formula Ba Cl2. It is one of the most common water-soluble salts of barium. Like most other water-soluble barium salts, it is white, highly toxic, and imparts a yellow-green coloration to a flame. ...
, and calcium chloride
Calcium chloride is an inorganic compound, a salt with the chemical formula . It is a white crystalline solid at room temperature, and it is highly soluble in water. It can be created by neutralising hydrochloric acid with calcium hydroxide.
Ca ...
was prepared, to which sodium carbonate
Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...
was added. The solution immediately precipitated
In an aqueous solution, precipitation is the process of transforming a dissolved substance into an insoluble solid from a super-saturated solution. The solid formed is called the precipitate. In case of an inorganic chemical reaction leading ...
, and after sitting for two weeks, the precipitate was identified as nearly pure benstonite.
History
Orlando J. Benston[ of ]Malvern, Arkansas
Malvern is a city in and the county seat of Hot Spring County, Arkansas, United States. Founded as a railroad stop at the eastern edge of the Ouachita Mountains, the community's history and economy have been tied to available agricultural and min ...
, visited a barite
Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate ( Ba S O4). Baryte is generally white or colorless, and is the main source of the element barium. The ''baryte group'' consists of baryte, celestine (strontium sulfate), ...
mine near the Magnet Cove igneous complex
The Magnet Cove igneous complex is a small alkalic ring complex lying to the west of the town of Magnet Cove in Hot Spring County, Arkansas.Geology of Titanium-Mineral Deposits, Eric R. Force, Geological Society of America, 1991,Google Books/ref ...
on New Year's Eve, 1954. He collected samples of a mineral that he guessed might be alstonite
Alstonite, also known as bromlite, is a low temperature hydrothermal mineral that is a rare double carbonate of calcium and barium with the formula , sometimes with some strontium. Barytocalcite and paralstonite have the same formula but different ...
or barytocalcite
Barytocalcite is an anhydrous barium calcium carbonate mineral with the chemical formula Ba Ca( C O3)2. It is trimorphous with alstonite and paralstonite, that is to say the three minerals have the same formula but different structures. Baryte a ...
on the basis of qualitative tests. Friedrich Lippmann identified it as a new mineral and described it in the journal ''Naturwissenschaften
''The Science of Nature'', formerly ''Naturwissenschaften'', is a monthly peer-reviewed scientific journal published by Springer Science+Business Media covering all aspects of the natural sciences relating to questions of biological significance. I ...
'' in 1961.Type specimens
In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes t ...
are held at Victor Goldschmidt University in Germany and the National Museum of Natural History
The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with 7 ...
in the United States.[
]
References
;Bibliography
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*
Further reading
*
External links
{{commonscat-inline, Benstonite
Trigonal minerals
Minerals in space group 148
Carbonate minerals
Magnesium minerals
Calcium minerals
Barium minerals