Hydroxycalciopyrochlore
Hydroxycalciopyrochlore is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Ca,Na,U, )₂(Nb,Ti)₂O₆(OH).
It crystallizes in the cubic crystal system (space group Fd-3m). It is a member of the Pyrochlore-Pyrochlore structural group.
Key properties: Mohs hardness 5–6; specific gravity 5.1; Brown streak; Adamantine to greasy luster.
IMA symbol Hcpcl, IMA status: approved, named in 2011.
Found in a rare-earth deposit in an alkali feldspar granite.
It is found associated with Calcite, barite, celestine, albite, aegirine, aegirine-augite, fluorite, parasite-(Ce), thorite, thorianite, zircon, galena, sphalerite, magnetite, pyrite.
The name refers to a member of the pyrochlore group with dominant hydroxol in the Y structural site and calcium in the A structural site.