| 词条 | Brushite |
| 释义 |
| name = Brushite | image = Bat_Guano_2.tif | imagesize = 260px | alt = | caption = Possible Brushite crystals (not confirmed) found in bat guano in Jamaica | category = Phosphate mineral | formula = {{chemical formula|Ca||H||PO4||·2||H2O}} | strunz = 8.CJ.50 | system = Monoclinic | class = Domatic (m) (same H-M symbol) | symmetry = Aa | unit cell = a = 6.265 Å, b = 15.19 Å, c = 5.814 Å; β = 116.47°; Z = 4 | color = Colorless to pale or ivory-yellow | habit = Prismatic to tabular acicular crystals; typically powdery or earthy | twinning = | cleavage = Perfect on {010} and {001} | fracture = | tenacity = Brittle | mohs = 2.5 | luster = Vitreous, pearly on cleavages | streak = | diaphaneity = Transparent to translucent | gravity = 2.328 | density = | polish = | opticalprop = Biaxial (+) | refractive = nα = 1.539 - 1.540 nβ = 1.544 - 1.546 nγ = 1.551 - 1.552 | birefringence = δ = 0.012 | pleochroism = | 2V = Measured: 59 to 87° | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = Readily in HCl | impurities = | alteration = | other = Piezoelectric | prop1 = | prop1text = | references = [1][2][3][4] }} Brushite is a phosphate mineral with the chemical formula {{chemical formula|Ca||H||PO4||·2||H2O}}. It forms colorless to pale yellow monoclinic prismatic crystals and as powdery or earthy masses.[2][4] It is the phosphate analogue of the arsenate pharmacolite and the sulfate gypsum. Discovery and occurrenceBrushite was first described in 1865 for an occurrence on Aves Island, Nueva Esparta, Venezuela, and named for the American mineralogist George Jarvis Brush (1831–1912).[3] It is believed to be a precursor of apatite and is found in guano-rich caves, formed by the interaction of guano with calcite and clay at a low pH. It occurs in phosphorite deposits and forms encrustations on old bones. It may result from runoff of fields which have received heavy fertilizer applications.[3] Associated minerals include tanarakite, ardealite, hydroxylapatite, variscite and gypsum.[2] Brushite is the original precipitating material in calcium phosphate kidney stones.[5] It is also one of the minerals present in dental calculi. References1. ^[https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Brushite Mineralienatlas] {{Phosphate-mineral-stub}}2. ^1 2 Brushite in the Handbook of Mineralogy 3. ^1 2 Brushite on Mindat.org 4. ^1 Webmineral data 5. ^{{cite web|title=Brushite|url=https://virtual-museum.soils.wisc.edu/display/brushite/|website=Virtual Museum of Molecules and Minerals|accessdate=22 December 2017}} 4 : Calcium minerals|Phosphate minerals|Cave minerals|Monoclinic minerals |
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