Santabarbaraite | |
---|---|
General | |
Category | Phosphate minerals |
Formula (repeating unit) | Fe3+3(PO4)2(OH)3·5H2O |
IMA symbol | Sbb [1] |
Strunz classification | 8.CE.80 |
Crystal system | Amorphous |
Identification | |
Color | Brown to light brown |
Crystal habit | Elongated or flattened prisms |
Twinning | None |
Cleavage | None, parting along {010} of replaced phase |
Fracture | Conchoidal |
Mohs scale hardness | Not determined |
Luster | Vitreous to greasy |
Streak | yellow-umber |
Diaphaneity | Translucent |
Specific gravity | 2.24 |
Optical properties | isotropic |
Refractive index | n = 1.659 |
Other characteristics | Pseudomorphism |
References | [2] [3] |
Santabarbaraite is an amorphous ferric hydroxy phosphate mineral hydrate that was discovered in Tuscany, Italy during 2000. [4] It also can be found in Victoria, Australia and Lake Baikal, Siberia. [5]
This phosphate mineral has a simplified formula Fe3+3(PO4)2(OH)3·5H2O, [4] which is the same formula of another non-amorphous phosphate mineral called allanpringite. [6] Santabarbaraite occurs as pseudomorphic masses after vivianite (Fe2+3(PO4)2·8H2O). In the process, monoclinic vivianite oxidizes to form the amorphous santabarbaraite. [4] Pseudomorphism may be seen in Victoria, Australia, in Wannon Falls (originally a well-known locality for vivianite). It also may be seen at Lake Baikal, Siberia where the oxidized santabarbaraite may be seen as a rim surrounding vivianite due to exposure to air. [5]
Due to pseudomorphism, Santabarbaraite samples show elongated and flattened prism habits. The bulk crystal color is brown to light brown, but appears yellow brown when viewed under an optical microscope. The streak color of the mineral is yellow-umber. [4] Santabarbaraite has a vitreous-to-greasy luster and shows no fluorescence under ultraviolet light. It is translucent and shows good parting along the cleavage of its original mineral vivianite at {010}. Santabarbaraite's density is 2.24 g/cm3. The mineral is isotropic, with refractive index n=1.659. [4]
Santabarbaraite is named after Santa Barbara, a mining district in Italy where, in 2000, the mineral was discovered and first described. The district name honors the saint of miners, Saint Barbara, [4] which by association, makes santabarbaraite one of few minerals bearing the name of a woman.
Santabarbaraite occurs in several places. It occurs in the Valderno Superiore lignite-bearing basin in the Santa Barbara mining district, Tuscany, Italy. [4] Santabarbaraite samples may be seen in Victoria, Australia, underlying Pliocene basalt beneath Wannon Falls. [4] It also is found in samples from Lake Baikal, Siberia. [5]
Since its discovery in 2000, this mineral hydrate has been found in the teeth of a living organism, the Gumboot chiton. [7] [8]
The term calcium phosphate refers to a family of materials and minerals containing calcium ions (Ca2+) together with inorganic phosphate anions. Some so-called calcium phosphates contain oxide and hydroxide as well. Calcium phosphates are white solids of nutritional value and are found in many living organisms, e.g., bone mineral and tooth enamel. In milk, it exists in a colloidal form in micelles bound to casein protein with magnesium, zinc, and citrate–collectively referred to as colloidal calcium phosphate (CCP). Various calcium phosphate minerals are used in the production of phosphoric acid and fertilizers. Overuse of certain forms of calcium phosphate can lead to nutrient-containing surface runoff and subsequent adverse effects upon receiving waters such as algal blooms and eutrophication (over-enrichment with nutrients and minerals).
Vivianite (Fe(II)
3(PO
4)
2·8H
2O) is a hydrated iron(II) phosphate mineral found in a number of geological environments. Small amounts of manganese Mn2+, magnesium Mg2+, and calcium Ca2+ may substitute for iron Fe2+ in its structure. Pure vivianite is colorless, but the mineral oxidizes very easily, changing the color, and it is usually found as deep blue to deep bluish green prismatic to flattened crystals. Vivianite crystals are often found inside fossil shells, such as those of bivalves and gastropods, or attached to fossil bone. Vivianite can also appear on the iron coffins or on the corpses of humans as a result of a chemical reaction of the decomposing body with the iron enclosure.
Torbernite, also known as chalcolite, is a relatively common mineral with the chemical formula Cu[(UO2)(PO4)]2(H2O)12. It is a radioactive, hydrated green copper uranyl phosphate, found in granites and other uranium-bearing deposits as a secondary mineral. The chemical formula of torbernite is similar to that of autunite in which a Cu2+ cation replaces a Ca2+ cation. Torbernite tends to dehydrate to metatorbernite with the sum formula Cu[(UO2)(PO4)]2(H2O)8.
Diadochite is a phospho-sulfate mineral. It is a secondary mineral formed by the weathering and hydration of other minerals. Its formula is Fe2(PO4)(SO4)OH·5H2O. Well crystallized forms are referred to as destinezite, which has been given official recognition by the International Mineralogical Association with diadochite being the poorly formed to amorphous variety.
Wavellite is an aluminium basic phosphate mineral with formula Al3(PO4)2(OH, F)3·5H2O. Distinct crystals are rare, and it normally occurs as translucent green radial or spherical clusters.
Phosphate minerals are minerals that contain the tetrahedrally coordinated phosphate anion, sometimes with arsenate and vanadate substitutions, along with chloride (Cl−), fluoride (F−), and hydroxide (OH−) anions, that also fit into the crystal structure.
Robertsite, Ca3(Mn3+)4[(OH)3| (PO4)2]2·3(H2O) (alternatively formulated Ca2(Mn3(PO4)3O2)(H2O)3), is a secondary phosphate mineral named for Willard Lincoln Roberts (1923–1987), mineralogist and professor at South Dakota School of Mines in Rapid City, South Dakota.
Aheylite is a rare phosphate mineral with formula (Fe2+Zn)Al6[(OH)4|(PO4)2]2·4(H2O). It occurs as pale blue to pale green triclinic crystal masses. Aheylite was made the newest member of the turquoise group in 1984 by International Mineralogical Association Commission on New Minerals and Mineral Names.
Arthurite is a mineral composed of divalent copper and iron ions in combination with trivalent arsenate, phosphate and sulfate ions with hydrogen and oxygen. Initially discovered by Sir Arthur Russell in 1954 at Hingston Down Consols mine in Calstock, Cornwall, England, arthurite is formed as a resultant mineral in the oxidation region of some copper deposits by the variation of enargite or arsenopyrite. The chemical formula of Arthurite is CuFe23+(AsO4,PO4,SO4)2(O,OH)2·4H2O.
Cacoxenite is an iron aluminium phosphate mineral with formula: Fe3+24Al(PO4)17O6(OH)12·17(H2O). Cacoxenite is associated with iron ores. The name comes from the Greek κăκός for "bad" or "evil" and ξένος for "guest" because the phosphorus content of cacoxenite lessens the quality of iron smelted from ore containing it.
Taranakite is a hydrated alkali iron-aluminium phosphate mineral with chemical formula (K,Na)3(Al,Fe3+)5(PO4)2(HPO4)6·18 H2O. It forms from the reaction of clay minerals or aluminous rocks with solutions enriched in phosphate derived from bat or bird guano or, less commonly, from bones or other organic matter. Taranakite is most commonly found in humid, bat inhabited caves near the boundary of guano layers with the cave surface. It is also found in perennially wet coastal locations that have been occupied by bird colonies. The type location, and its namesake, the Sugar Loaf Islands off Taranaki, New Zealand, is an example of a coastal occurrence.
Anapaite is a calcium–iron phosphate mineral with formula: Ca2Fe2+(PO4)2·4H2O. It is a mineral that typically occurs in cavities in fossil bearing sedimentary rocks. It is also found in phosphate bearing iron ores and rarely in pegmatites. It is commonly found with goethite, siderite and vivianite.
Cyrilovite (NaFe33+(PO4)2(OH)4·2(H2O)) is a hydrous sodium iron phosphate mineral. It is isomorphous and isostructural with wardite, the sodium aluminium counterpart.
Hureaulite is a manganese phosphate with the formula Mn2+5(PO3OH)2(PO4)2·4H2O. It was discovered in 1825 and named in 1826 for the type locality, Les Hureaux, Saint-Sylvestre, Haute-Vienne, Limousin, France. It is sometimes written as huréaulite, but the IMA does not recommend this for English language text.
This list gives an overview of the classification of non-silicate minerals and includes mostly International Mineralogical Association (IMA) recognized minerals and its groupings. This list complements the List of minerals recognized by the International Mineralogical Association series of articles and List of minerals. Rocks, ores, mineral mixtures, not IMA approved minerals, not named minerals are mostly excluded. Mostly major groups only, or groupings used by New Dana Classification and Mindat.
Zinclipscombite is a dark-green to brown zinc iron phosphate mineral with the formula Zn(Fe3+)2(PO4)2(OH)2. It occurs as fibrous spheres and exhibits tetragonal crystal structure.
Allanpringite is a phosphate mineral named after Australian mineralogist Allan Pring of the South Australian Museum. Allanpringite is a Fe3+ analogue Al-phosphate mineral wavellite, but it has a different crystal symmetry – monoclinic instead of orthorhombic in wavellite. It forms needle-like crystals, which are always twinned and form parallel bundles up to about 2 mm long. They are often found in association with other iron phosphates in abandoned iron mines.
Penikisite was discovered by Alan Kulan and Gunar Penikis near Rapid Creek, Yukon Territory. The mineral is a member of the bjarebyite group along with kulanite, ideally BaFe2+2Al2(PO4)3(OH)3, and bjarebyite, ideally BaMn2+2Al2(PO4)3(OH)3. It is among several new minerals that have been discovered in the Rapid Creek and Big Fish areas of Yukon Territory. Kulanite is similar in many ways to penikisite in appearance and properties. The chemical formula for penikisite is Ba(Mg,Fe,Ca)Al2(PO4)2(OH)3. It has a hardness of about 4 and a density of 3.79 g/cm3. Penikisite is unique among the bjarebyite group in being monoclinic and has a biaxial optical class. It comes in shades of blue and green and, when rubbed on a streak plate, is pale green to white in color. Although penikisite and kulanite both range from blue to green, penikisite zones are easily distinguishable from kulanite zones in kulanite-penikisite crystals because they are lighter than the darker kulanite in color. Penikisite is a phosphate and is different from kulanite in that it is a magnesium-rich phosphate whereas kulanite is an iron-rich phosphate.
Metavivianite is a hydrated iron phosphate mineral found in a number of geological environments. As a secondary mineral it is typically formed from oxidizing vivianite. Metavivianite is typically found as dark blue or dark green prismatic to flattened crystals.
The phosphate sulfates are mixed anion compounds containing both phosphate and sulfate ions. Related compounds include the arsenate sulfates, phosphate selenates, and arsenate selenates.