Microphoto of Brockite [(Ca,Th,Ce)PO4·H2O] on Thorite [(Th, U) SiO4]. Field view: 2 x 2 mm. Brockite is covering thorite like as as yellow-brownish thin crust of alteration. From Mogok Township, Distrito Pyin-Oo-Lwin, Division Mandalay, Burma (Myanmar). Raúl Jorge Tauber Larry´s collection. — Photo: Raúl Jorge Tauber Larry · CC0
Brockite
A rare-earth phosphate that crystallizes in a chiral hexagonal space group, usually as granular masses.
Intro adapted from Wikipedia (CC BY-SA).
Brockite is an IMA-recognized mineral species in the phosphate class, with the chemical formula (Ca,Th,Ce)(PO₄)·H₂O.
It crystallizes in the hexagonal crystal system (space group P6_222). It is a member of the Rhabdophane structural group.
Key properties: specific gravity 3.9; Greasy to vitreous luster; optically uniaxial.
IMA symbol Bck, IMA status: approved, named in 1962.
Found as a rare accessory mineral in granite and granite pegmatites.
It is found associated with Monazite, bastnäsite, xenotime, thorite, zircon, apatite, rutile, hematite.
The mineral was named to honor Maurice R. Brock, U.S. Geological Survey, who supplied the first specimen.