Tantalite-(Mn) Locality: Alto Ligonha pegmatites, Alto Ligonha District, Zambezia Province , Mozambique ( Locality at mindat.org ) Size: 2.0 x 0.9 x 0.4 cm. A sharp, tabular, gemmy and lustrous, beautifully cherry-red manganotantalite crystal from the Alta Ligonha pegmatites of Mozambique. The partially contacted termination and one cleaved edge are noted, but this remains a gemmier than normal, highly representative example of the species and locale from the John White Collection. He purchased this piece from Pala Properties in 1972. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Tantalite-(Mn)
The mineral group tantalite [(Fe, Mn)Ta2O6] is the primary source of the chemical element tantalum, a corrosion (heat and acid) resistant metal. It is chemically similar to columbite, and the two are often grouped together as a semi-singular mineral called coltan or "columbite-tantalite" in many mineral guides. However, tantalite has a much greater specific gravity than columbite (8.0+ compared to columbite's 5.2). Iron-rich tantalite is the mineral tantalite-(Fe) or ferrotantalite and manganese-rich is tantalite-(Mn) or manganotantalite. Tantalite is also very close to tapiolite.
Intro adapted from Wikipedia (CC BY-SA).
Tantalite-(Mn) is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Mn²⁺Ta₂O₆.
It crystallizes in the orthorhombic crystal system (space group Pbcn). It is a member of the Columbite structural group.
Key properties: Mohs hardness 6; specific gravity 6.65–8; Red, scarlet to black streak; Submetallic to vitreous luster; optically biaxial.
IMA symbol Ttl-Mn, IMA status: approved, named in 1877.
An accessory and primary constituent of granite pegmatites; detrital in placers.
It is found associated with [Albite, microcline, beryl, lepidolite, muscovite, tourmaline, spodumene, lithiophilite, triphylite, amblygonite, triplite, samarskite, apatite, microlite.
Suffix for dominant Mn in the composition and relation to tantalite-(Fe) and tantalite-(Mg), named for the Greek mythical Tantalus, for the difficulty in bringing the mineral into solution.