Oxycalciomicrolite
Oxycalciomicrolite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Ca₂Ta₂O₇.
It crystallizes in the cubic crystal system (space group Fd-3m). It is a member of the Pyrochlore-microlite structural group.
Key properties: Mohs hardness 5–5.5; specific gravity 6.333; White streak; Vitreous to resinous luster.
IMA symbol Ocmic, IMA status: approved, named in 2020.
Found in the saprolite of a weathered granitic pegmatite.
It is found associated with Columbite subgroup minerals, cassiterite, hematite, ilmenite, monazite-(Ce), epidote- group minerals, xenotime-(Y), zircon, beryl, spinel, garnet-group minerals.
The first prefix, oxy, indicates dominant oxygen at the Y site, the second prefix, calcio, indicates the dominant calcium in the A site of a member of the microlite subgroup.