Apatite
Apatite group | ||
---|---|---|
Specific gravity 3.16–3.22[2] | | |
Polish luster | Vitreous[3] | |
Optical properties | Double refractive, uniaxial negative[3] | |
Refractive index | 1.634–1.638 (+0.012, −0.006)[3] | |
Birefringence | 0.002–0.008[3] | |
Pleochroism | Blue stones – strong, blue and yellow to colorless. Other colors are weak to very weak.[3] | |
Dispersion | 0.013[3] | |
Ultraviolet fluorescence | Yellow stones – purplish-pink, which is stronger in long wave; blue stones – blue to light-blue in both long and short wave; green stones – greenish-yellow, which is stronger in long wave; violet stones – greenish-yellow in long wave, light-purple in short wave.[3] |
Apatite is a group of
The mineral was named apatite by the German
Geology
Apatite is very common as an
Apatite is the defining mineral for 5 on the
Apatite is one of a few minerals produced and used by biological micro-environmental systems.[7] Hydroxyapatite, also known as hydroxylapatite, is the major component of tooth enamel and bone mineral. A relatively rare form of apatite in which most of the OH groups are absent and containing many carbonate and acid phosphate substitutions is a large component of bone material.[13]
Fluorapatite (or fluoroapatite) is more resistant to acid attack than is hydroxyapatite; in the mid-20th century, it was discovered that communities whose water supply naturally contained fluorine had lower rates of
Fission tracks in apatite are commonly used to determine the thermal histories of orogenic belts and of sediments in sedimentary basins.[16] (U-Th)/He dating of apatite is also well established from noble gas diffusion studies[17][18][19][20][21][22][23] for use in determining thermal histories[24][25] and other, less typical applications such as paleo-wildfire dating.[26]
Uses
The primary use of apatite is as a source of phosphate in the manufacture of
During digestion of apatite with sulfuric acid to make phosphoric acid, hydrogen fluoride is produced as a byproduct from any fluorapatite content. This byproduct is a minor industrial source of hydrofluoric acid.[30] Apatite is also occasionally a source of uranium and vanadium, present as trace elements in the mineral.[27]
Fluoro-chloro apatite forms the basis of the now obsolete Halophosphor fluorescent tube phosphor system. Dopant elements of manganese and antimony, at less than one mole-percent – in place of the calcium and phosphorus impart the fluorescence – and adjustment of the fluorine-to-chlorine ratio alter the shade of white produced. This system has been almost entirely replaced by the Tri-Phosphor system.[31]
Apatites are also a proposed host material for storage of
Gemology
Apatite is infrequently used as a
Use as an ore mineral
Apatite is occasionally found to contain significant amounts of
The town of Apatity in the Arctic North of Russia was named for its mining operations for these ores.
Apatite is an ore mineral at the Hoidas Lake rare-earth project.[40]
Thermodynamics
The standard enthalpies of formation in the crystalline state of hydroxyapatite, chlorapatite and a preliminary value for bromapatite, have been determined by reaction-solution calorimetry. Speculations on the existence of a possible fifth member of the calcium apatites family, iodoapatite, have been drawn from energetic considerations.[41]
Structural and thermodynamic properties of crystal hexagonal calcium apatites, Ca10(PO4)6(X)2 (X= OH, F, Cl, Br), have been investigated using an all-atom Born-Huggins-Mayer potential[42] by a molecular dynamics technique. The accuracy of the model at room temperature and atmospheric pressure was checked against crystal structural data, with maximum deviations of c. 4% for the haloapatites and 8% for hydroxyapatite. High-pressure simulation runs, in the range 0.5–75 kbar, were performed in order to estimate the isothermal compressibility coefficient of those compounds. The deformation of the compressed solids is always elastically anisotropic, with BrAp exhibiting a markedly different behavior from those displayed by HOAp and ClAp. High-pressure p-V data were fitted to the Parsafar-Mason equation of state[43] with an accuracy better than 1%.[44]
The monoclinic solid phases Ca10(PO4)6(X)2 (X= OH, Cl) and the molten hydroxyapatite compound have also been studied by molecular dynamics.[45][46]
Lunar science
Bio-leaching
The ectomycorrhizal fungi Suillus granulatus and Paxillus involutus can release elements from apatite. Release of phosphate from apatite is one of the most important activities of mycorrhizal fungi,[51] which increase phosphorus uptake in plants.[52]
Apatite group and supergroup
Apatite is the prototype of a class of chemically, stoichometrically or structurally similar minerals, biological materials, and synthetic chemicals.
Apatites have been investigated for their potential use as pigments (copper-doped alkaline earth apatites), as phosphors and for absorbing and immobilising toxic heavy metals.
In apatite minerals strontium, barium and lead can be substituted for calcium; arsenate and vanadate for phosphate; and the final balancing anion can be fluoride (fluorapatites), chloride (chlorapatites), hydroxide (hydroxyapatites) or oxide (oxyapatites). Synthetic apatites add hypomanganate, hypochromate, bromide (bromoapatites), iodide (iodoapatites), sulfide (sulfoapatites), and selenide (selenoapatites). Evidence for natural sulfide substitution has been found in lunar rock samples.[54]
Furthermore, compensating substitution of monovalent and trivalent cations for calcium, of dibasic and tetrabasic anions for phosphate, and of the balancing anion, can occur to a greater or lesser degree. For example, in biological apatites there is appreciable substitution of sodium for calcium and carbonate for phosphate, in belovite sodium and cerium or lanthanum substitute for a pair of divalent metal ions, in germanate-pyromorphite germanate replaces phosphate and chloride, and in ellestadites silicate and sulphate replace pairs of phosphate anions. Metals forming smaller divalent ions, such as magnesium and iron, cannot substitute extensively for the relatively large calcium ions but may be present in small quantities.[55]
See also
References
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- ^ a b c d Apatite. Webmineral
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- ^ According to Werner himself – (Werner, 1788), p. 85 – the name "apatite" first appeared in print in:
- Gerhard, C.A., Grundriss des Mineral-systems [Outline of the system of minerals] (Berlin, (Germany): Christian Friedrich Himburg, 1786), p. 281. From p. 281: "Von einigen noch nicht genau bestimmten und ganz neu entdeckten Mineralien. Ich rechne hierzu folgende drei Körper: 1. Den Apatit des Herrn Werners. … "(On some still not precisely determined and quite recently discovered minerals. I count among these the following three substances: 1. the apatite of Mr. Werner. … )
- Werner, A.G. (1788) "Geschichte, Karakteristik, und kurze chemische Untersuchung des Apatits" (History, characteristics, and brief chemical investigation of apatite), Bergmännisches Journal (Miners' Journal), vol. 1, pp. 76–96. On pp. 84–85, Werner explained that because mineralogists had repeatedly misclassified it (e.g., as aquamarine), he gave apatite the name of "deceiver": "Ich wies hierauf diesem Foßile, als einer eigenen Gattung, sogleich eine Stelle in dem Kalkgeschlechte an; und ertheilte ihm, – weil es bisher alle Mineralogen in seiner Bestimmung irre geführt hatte, – den Namen Apatit, den ich von dem griechischen Worte απατάω (decipio) bildete, und welcher so viel as Trügling sagt." (I then immediately assigned to this fossil [i.e., material obtained from underground], as a separate type, a place in the lime lineage; and conferred on it – because it had previously led astray all mineralogists in its classification – the name "apatite", which I formed from the Greek word απατάω [apatáō] (I deceive) and which says as much as [the word] "deceiver".)
- ^ "ἀπατάω". Logeion. Archived from the original on Feb 22, 2023. Retrieved Feb 22, 2023.
- ^ "Fluorapatite mineral information and data". mindat.org. Retrieved 30 January 2018.
- ^ ISBN 9780195106916.
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- ^ Herm, C.; Thieme, C.; Emmerling, E.; Wu, Y.Q.; Zhou, T.; Zhang, Z. (1995). "Analysis of painting materials of the polychrome terracotta army of the first Emperor Qin Shi Huang". Arbeitsheft des Bayerischen Landesamtes für Denkmalpflege: 675–84. Retrieved 30 July 2021.
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- ^ Streeter, Edwin W., Precious Stones and Gems 6th edition, George Bell and Sons, London, 1898, p. 306
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- ^ Haxel G, Hedrick J, Orris J. 2006. Rare earth elements critical resources for high technology. Reston (VA): United States Geological Survey. USGS Fact Sheet: 087‐02.
- ^ Proctor, Robert N. (2006-12-01) Puffing on Polonium – New York Times. Nytimes.com. Retrieved on 2011-07-24.
- ^ Tobacco Smoke | Radiation Protection | US EPA. Epa.gov (2006-06-28). Retrieved on 2011-07-24.
- ^ Great Western Minerals Group Ltd. | Projects – Hoidas Lake, Saskatchewan Archived 2008-07-01 at the Wayback Machine. Gwmg.ca (2010-01-27). Retrieved on 2011-07-24.
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- ^ See: Born-Huggins-Mayer potential (SklogWiki)
- ^ Parsafar, Gholamabbas and Mason, E.A. (1994) "Universal equation of state for compressed solids," Physical Review B Condensed Matter, 49 (5) : 3049–60.
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