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.
The mineral was named apatite by the German geologistAbraham Gottlob Werner in 1786, although the specific mineral he had described was reclassified as fluorapatite in 1860 by the German mineralogistKarl Friedrich August Rammelsberg. Apatite is often mistaken for other minerals. This tendency is reflected in the mineral's name, which is derived from the Greek word ? (apatein), which means to deceive or to be misleading.
While apatite is most commonly a sedimentary rock, different forms of apatite can be formed in both sedimentary processes, igneous processes (e.g., Pegmatite), and in hydrothermal vents, as well as production by biological systems.
Apatite is one of a few minerals produced and used by biological micro-environmental systems. Apatite is the defining mineral for 5 on the Mohs scale. 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.
The primary use of apatite is in the manufacture of fertilizer - it is a source of phosphorus. It is occasionally used as a gemstone. Green and blue varieties, in finely divided form, are pigments with excellent covering power.
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.
In the United States, apatite-derived fertilizers are used to supplement the nutrition of many agricultural crops by providing a valuable source of phosphate.
Apatites are also a proposed host material for storage of nuclear waste, along with other phosphates.
Faceted blue apatite, Brazil
Apatite is infrequently used as a gemstone. Transparent stones of clean color have been faceted, and chatoyant specimens have been cabochon-cut. Chatoyant stones are known as cat's-eye apatite, transparent green stones are known as asparagus stone, and blue stones have been called moroxite. If crystals of rutile have grown in the crystal of apatite, in the right light the cut stone displays a cat's-eye effect. Major sources for gem apatite are Brazil, Myanmar, and Mexico. Other sources include Canada, Czech Republic, Germany, India, Madagascar, Mozambique, Norway, South Africa, Spain, Sri Lanka, and the United States.
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.
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 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 with an accuracy better than 1%.
The monoclinic solid phases Ca10(PO4)6(X)2 (X= OH, Cl) and the molten hydroxyapatite compound have also been studied by molecular dynamics.
Moon rocks collected by astronauts during the Apollo program contain traces of apatite. Re-analysis of these samples in 2010 revealed water trapped in the mineral as hydroxyl, leading to estimates of water on the lunar surface at a rate of at least 64 parts per billion - 100 times greater than previous estimates - and as high as 5 parts per million. If the minimum amount of mineral-locked water was hypothetically converted to liquid, it would cover the Moon's surface in roughly one meter of water.
^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 described the mineral in some detail in an article of 1788.
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 (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 [apatao] (I deceive) and which says as much as [the word] "deceiver".)
^McDannell, Kalin T.; Zeitler, Peter K.; Janes, Darwin G.; Idleman, Bruce D.; Fayon, Annia K. (February 2018). "Screening apatites for (U-Th)/He thermochronometry via continuous ramped heating: He age components and implications for age dispersion". Geochimica et Cosmochimica Acta. 223: 90-106. Bibcode:2018GeCoA.223...90M. doi:10.1016/j.gca.2017.11.031. ISSN0016-7037.
^House, M.A.; Wernicke, B.P.; Farley, K.A.; Dumitru, T.A. (October 1997). "Cenozoic thermal evolution of the central Sierra Nevada, California, from (UTh)/He thermochronometry". Earth and Planetary Science Letters. 151 (3-4): 167-179. doi:10.1016/s0012-821x(97)81846-8. ISSN0012-821X.
^Reiners, P. W.; Thomson, S. N.; McPhillips, D.; Donelick, R. A.; Roering, J. J. (2007-10-12). "Wildfire thermochronology and the fate and transport of apatite in hillslope and fluvial environments". Journal of Geophysical Research. 112 (F4): F04001. Bibcode:2007JGRF..112.4001R. doi:10.1029/2007jf000759. ISSN0148-0227.
^Villalba, Gara; Ayres, Robert U.; Schroder, Hans (2008). "Accounting for Fluorine: Production, Use, and Loss". Journal of Industrial Ecology. 11: 85-101. doi:10.1162/jiec.2007.1075.
^Salvi S, Williams-Jones A. 2004. Alkaline granite-syenite deposits. In Linnen RL, Samson IM, editors. Rare element geochemistry and mineral deposits. St. Catharines (ON): Geological Association of Canada. pp. 315-341 ISBN1-897095-08-2
^Parsafar, Gholamabbas and Mason, E.A. (1994) "Universal equation of state for compressed solids," Physical Review B Condensed Matter, 49 (5) : 3049-3060.
^Cruz, F.J.A.L.; Canongia Lopes, J.N.; Calado, J.C.G.; Minas da Piedade, M.E. (2005). "A Molecular Dynamics Study of the Thermodynamic Properties of Calcium Apatites. 1. Hexagonal Phases". J. Phys. Chem. B. 109 (51): 24473-24479. doi:10.1021/jp054304p. PMID16375450.
^Cruz, F.J.A.L.; Canongia Lopes, J.N.; Calado, J.C.G. (2006). "Molecular Dynamics Study of the Thermodynamic Properties of Calcium Apatites. 2. Monoclinic Phases". J. Phys. Chem. B. 110 (9): 4387-4392. doi:10.1021/jp055808q. PMID16509739.
^Smith, J. V.; Anderson, A. T.; Newton, R. C.; Olsen, E. J.; Crewe, A. V.; Isaacson, M. S. (1970). "Petrologic history of the moon inferred from petrography, mineralogy and petrogenesis of Apollo 11 rocks". Geochimica et Cosmochimica Acta. 34, Supplement 1: 897-925. Bibcode:1970GeCAS...1..897S. doi:10.1016/0016-7037(70)90170-5.