Oxybismutomicrolite
Oxybismutomicrolite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Bi₁.₃₃ ₀.₆₇)Ta₂O₆O.
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; specific gravity 6.98; Grayish-white streak.
IMA symbol Obmic, IMA status: approved, named in 2019.
Found in complex granitic miarolitic pegmatite, enriched in bismuth.
It is found associated with Albite, lepidolite, elbaite, Bi-rich fluornatromicrolite, bismutotantalite, stibiotantalite.
The name refers to a member of the microlite group with prefixes to indicate essential oxygen (oxy) in the Y site and essential Bi3+ (bismuto) in the A site.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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