Tantalite-(Mn)

tantalite-(Mn)

tantalite-(Fe)

tantalite-(Mg)

columbite-(Mn)

Images

Formula: Mn2+Ta2O6
One of the tantalite minerals. Multiple oxide, columbite group, tantalum-bearing mineral, forms series with tantalite-(Fe) and with columbite-(Mn)
Specific gravity: 8.1
Hardness: 6 - 6½
Streak: brown
Colour: Black, brown
Solubility: Insoluble in hydrochloric and nitric acid; slightly soluble in sulphuric acid
Common impurities: Fe,Nb
Environments:

Pegmatites

Tantalite-(Mn) occurs as an accessory and primary constituent of granitic pegmatites, and is detrital in placers. Associated minerals include albite, microcline, beryl, lepidolite, muscovite, tourmaline, spodumene, lithiophilite, triphylite, amblygonite, triplite, samarskite, apatite, microlite and cassiterite (HOM).

Localities

At the Lipovsk pegmatite field, Rezhevsky District, Sverdlovsk Oblast, Russia, intergrowths of tantalite-(Mg), tantalite-(Fe), columbite-(Fe) and uranium-bearing microlite form rims on tantalite-(Mn) crystals in albite variety andesine-calcite nests in a deeply desilicated granite pegmatite which crosscuts serpentinite near its contact with marble. Other associated minerals include dravite-uvite, chrysoberyl, phlogopite, magnesio-hornblende to edenite, cordierite, phenakite and clinochlore (Minrec 35.4.356-357).

The type locality is the Utö mines, Utö, Haninge, Stockholm County, Sweden.

At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, tantalite-(Mn) is common in the core-margin area, and occurs in muscovite-rich pockets. It forms the inner portion of composite wodginite/tantalite-(Mn) crystals. The Emmons pegmatite is situated in a belt of metasedimentary rocks which originated as marine sediments which were subsequently deformed and metamorphosed. It is a highly evolved boron-lithium-cesium-tantalum enriched pegmatite (R&M 94.6.516).

Back to Minerals