{{infobox mineral | name = Brockite | image = Brockite-Thorite-474862.jpg | alt = | caption = Microphoto of brockite on thorite (black). <br>Field view: 2 x 2 mm. | category = Phosphate mineral | formula = (Ca,Th,Ce)PO<sub>4</sub>·H<sub>2</sub>O | IMAsymbol=Bck<ref>{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}</ref> | molweight = | strunz = 8.CJ.45 | dana = | system = Hexagonal | class = Trapezohedral (622) <br>H-M symbol: (622) | symmetry = ''P''6<sub>2</sub>22 or ''P''6<sub>4</sub>22 | unit cell = a = 6.98&nbsp;Å, c = 6.40&nbsp;Å; Z&nbsp;=&nbsp;3 | color = Reddish brown, yellow (red brown due to inclusions of hematite) | colour = | habit = Rarely as Stubby hexagonal prisms rare; common as granular massive aggregates, cryptocrystalline | twinning = | cleavage = None observed | fracture = Conchoidal | tenacity = Brittle | mohs = 3 - 4 | luster = Greasy to vitreous | streak = | diaphaneity = Translucent to opaque | gravity = 3.9 (measured) | density = | polish = | opticalprop = Uniaxial (+) | refractive = n<sub>ω</sub> = 1.680 n<sub>ε</sub> = 1.695 | birefringence = δ = 0.015 | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = Radioactive | prop1 = | prop1text = | references = <ref name=HBM>[http://rruff.info/doclib/hom/brockite.pdf Brockite in the Handbook of Mineralogy]</ref><ref name=Mindat>[http://www.mindat.org/min-780.html Brockite on Mindat.org]</ref><ref name=Webmin>[http://www.webmineral.com/data/Brockite.shtml Brockite data on Webmineral]</ref> }} '''Brockite''' is a rare earth phosphate mineral with formula: {{Chem2|(Ca,Th,Ce)PO4·H2O}}. It crystallizes in the hexagonal system in the chiral space group 180 or its enantiomorph 181. It is typically granular to massive with only rare occurrence of stubby crystals. It is radioactive due to the thorium content.

==Discovery and occurrence== Brockite was first described in 1962 for an occurrence in the Bassick Mine area, Querida, Wet Mountains, Custer County, Colorado, US. It was named for Maurice R. Brock, of the U.S. Geological Survey.<ref name=Mindat/>

Brockite occurs in granite and granite pegmatite as an accessory mineral. Associated minerals include monazite, bastnasite, xenotime, thorite, zircon, apatite, rutile and hematite.<ref name=HBM/>

==References== {{reflist}}

Category:Phosphate minerals Category:Hexagonal minerals Category:Minerals in space group 180 or 181

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