{{Infobox mineral | name = Polycrase | boxwidth = | boxbgcolor = | image = Polycrase-(Y)-619586.jpg | imagesize = | alt = | caption = Polycrase crystal from Rio Pomba, Minas Gerais, Brazil | struct image = | struct caption = | struct imagesize = | struct2 image = | struct2 caption = | struct2 imagesize= | SMILES = | Jmol = | category = | formula = {{chem2|(Y,Ca,Ce,U,Th)(Ti,Nb,Ta)2O6}} | IMAsymbol = Plc<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 = | dana = | system = | class = | symmetry = | unit cell = | color = | colour = | habit = | twinning = | cleavage = | fracture = | tenacity = | toughness = | mohs = 5-6 | luster = | streak = | diaphaneity = | gravity = 5 | density = | polish = | opticalprop = | refractive = | birefringence = | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | Curie temp = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = 25px Radioactive | prop1 = | prop1text = | references = | var1 = | var1text = | var2 = | var2text = | var3 = | var3text = | var4 = | var4text = | var5 = | var5text = | var6 = | var6text = }} '''Polycrase''' or '''polycrase-(Y)''' is a black or brown metallic complex uranium yttrium oxide mineral with the chemical formula {{chem2|(Y,Ca,Ce,U,Th)(Ti,Nb,Ta)2O6}}. It is amorphous. It has a Mohs hardness of 5 to 6 and a specific gravity of 5. It is radioactive due to its uranium content (around 6%). It occurs in granitic pegmatites.
Polycrase forms a continuous series with the niobium rich rare earth oxide euxenite.
It was first described in 1870 at Rasvåg on the island of Hidra, south of the town of Flekkefjord, Norway. It is found in Sweden, Norway, and the United States.
==References== {{Reflist}}
==External links== *[http://www.mindat.org/min-3257.html Mindat with location data] *[http://webmineral.com/data/Polycrase-(Y).shtml Webmineral]
{{Titanium minerals}}
Category:Uranium minerals Category:Thorium minerals Category:Calcium minerals Category:Cerium minerals Category:Yttrium minerals Category:Lanthanide minerals Category:Niobium minerals Category:Tantalum minerals Category:Titanium minerals Category:Oxide minerals Category:Amorphous solids Category:Orthorhombic minerals Category:Minerals in space group 60 Category:Minerals described in 1870
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