Hydroxyplumbopyrochlore
Hydroxyplumbopyrochlore is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Pb₁.₅ ₀.₅)Nb₂O₆(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 5.5; specific gravity 6.474; White streak; Adamantine luster.
IMA symbol Hppcl, IMA status: approved, named in 2020.
From pegmatite-aplite in a peralkaline granitic complex.
It is found associated with Quartz, microcline, “biotite, ” rutile, zircon, calcite, rhodochrosite, columbite-(Fe), goethite, thorite, bastnäsite-(Ce), xenotime-(Y), samarskite-(Y).
The first prefix, hydroxy, indicates dominant OH at the Y site, the second prefix, plumbo, indicates the dominant lead in the A site of a member of the pyrochlore subgroup.