Clintonite
Encyclopedia
Clintonite is a calcium
magnesium
aluminium
phyllosilicate mineral. It is a member of the margarite
group of mica
s and the subgroup often referred to as the "brittle" micas. Clintonite has the chemical formula
: Ca(Mg,Al)3(Al3Si)O10(OH)2. Like other micas and chlorite
s, clintonite is monoclinic in crystal form and has a perfect basal cleavage
parallel to the flat surface of the plates or scales. The Mohs hardness of clintonite is 6.5, and the specific gravity
is 3.0 to 3.1. It occurs as variably colored, colorless, green, yellow, red, to reddish-brown masses and radial clusters.
The brittle micas differ chemically from the micas in containing less silica and no alkali
s, and from the chlorites in containing much less water; in many respects, they are intermediate between the micas and chlorites. Clintonite and its iron
-rich variety xanthophyllite are sometimes considered the calcium analogues of the phlogopite
s.
Typical formation environment is in serpentinized
dolomitic limestones
and contact metamorphosed skarn
s. It occurs with talc
, spinel
, grossular
, vesuvianite
, clinopyroxene, monticellite
, chondrodite
, phlogopite
, chlorite
, quartz
, calcite
and dolomite
.
Clintonite was first described in 1843 for an occurrence in Orange County, New York
. It was named for De Witt Clinton (1769-1828).
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
phyllosilicate mineral. It is a member of the margarite
Margarite
Margarite is a calcium rich member of the mica group of the phyllosilicates with formula: CaAl2O102. It forms white to pinkish or yellowish gray masses or thin laminae. It crystallizes in the monoclinic crystal system. It typically has a specific gravity of around 3 and a Mohs hardness of 4...
group of mica
Mica
The mica group of sheet silicate minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic, with a tendency towards pseudohexagonal crystals, and are similar in chemical composition...
s and the subgroup often referred to as the "brittle" micas. Clintonite has the chemical formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
: Ca(Mg,Al)3(Al3Si)O10(OH)2. Like other micas and chlorite
Chlorite group
The chlorites are a group of phyllosilicate minerals. Chlorites can be described by the following four endmembers based on their chemistry via substitution of the following four elements in the silicate lattice; Mg, Fe, Ni, and Mn....
s, clintonite is monoclinic in crystal form and has a perfect basal cleavage
Cleavage (crystal)
Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite crystallographic structural planes. These planes of relative weakness are a result of the regular locations of atoms and ions in the crystal, which create smooth repeating surfaces that are visible both in the...
parallel to the flat surface of the plates or scales. The Mohs hardness of clintonite is 6.5, and the specific gravity
Specific gravity
Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...
is 3.0 to 3.1. It occurs as variably colored, colorless, green, yellow, red, to reddish-brown masses and radial clusters.
The brittle micas differ chemically from the micas in containing less silica and no alkali
Alkali
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...
s, and from the chlorites in containing much less water; in many respects, they are intermediate between the micas and chlorites. Clintonite and its iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
-rich variety xanthophyllite are sometimes considered the calcium analogues of the phlogopite
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 KMg3AlSi3O102. Iron substitutes for magnesium in variable amounts...
s.
Typical formation environment is in serpentinized
Serpentinite
Serpentinite is a rock composed of one or more serpentine group minerals. Minerals in this group are formed by serpentinization, a hydration and metamorphic transformation of ultramafic rock from the Earth's mantle...
dolomitic limestones
Dolostone
Dolostone or dolomite rock is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite. In old U.S.G.S. publications it was referred to as magnesian limestone. Most dolostone formed as a magnesium replacement of limestone or lime mud prior to lithification. It is...
and contact metamorphosed skarn
Skarn
Skarn is an old Swedish mining term originally used to describe a type of silicate gangue, or waste rock, associated with iron-ore bearing sulfide deposits apparently replacing Archean age limestones in Sweden's Persberg mining district. In modern usage the term "skarn" has been expanded to refer...
s. It occurs with talc
Talc
Talc is a mineral composed of hydrated magnesium silicate with the chemical formula H2Mg34 or Mg3Si4O102. In loose form, it is the widely-used substance known as talcum powder. It occurs as foliated to fibrous masses, its crystals being so rare as to be almost unknown...
, spinel
Spinel
Spinel is the magnesium aluminium member of the larger spinel group of minerals. It has the formula MgAl2O4. Balas ruby is an old name for a rose-tinted variety.-Spinel group:...
, grossular
Grossular
Grossular or grossularite is a calcium-aluminium mineral species of the garnet group with the formula Ca3Al23, though the calcium may in part be replaced by ferrous iron and the aluminium by ferric iron. The name grossular is derived from the botanical name for the gooseberry, grossularia, in...
, vesuvianite
Vesuvianite
Vesuvianite, also known as idocrase, is a green, brown, yellow, or blue silicate mineral. Vesuvianite occurs as tetragonal crystals in skarn deposits and limestones that have been subjected to contact metamorphism...
, clinopyroxene, monticellite
Monticellite
Monticellite and kirschsteinite are gray silicate minerals of the olivine group with compositions CaMgSiO4 and CaFeSiO4, respectively. Most monticellites have the pure magnesium end-member composition but rare ferroan monticellites and magnesio-kirschsteinite are found with between 30 and 75 mol.%...
, chondrodite
Chondrodite
Chondrodite is a nesosilicate mineral with formula 522. Although it is a fairly rare mineral, it is the most frequently encountered member of the humite group of minerals. It is formed in hydrothermal deposits from locally metamorphosed dolomite. It is also found associated with skarn and...
, phlogopite
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 KMg3AlSi3O102. Iron substitutes for magnesium in variable amounts...
, chlorite
Chlorite
The chlorite ion is ClO2−. A chlorite is a compound that contains this group,with chlorine in oxidation state +3. Chlorites are also known as salts of chlorous acid.-Oxidation states:...
, quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
, calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
and dolomite
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
.
Clintonite was first described in 1843 for an occurrence in Orange County, New York
Orange County, New York
Orange County is a county located in the U.S. state of New York. It is part of the Poughkeepsie–Newburgh–Middletown, NY Metropolitan Statistical Area and is located at the northern reaches of the New York metropolitan area. The county sits in the state's scenic Mid-Hudson Region of the Hudson Valley...
. It was named for De Witt Clinton (1769-1828).