Stibiotantalite - Occurrence, Properties, and Distribution

Stibiotantalite is a member of the Cervantite family. It was first discovered in Greenbushes tin placers of the Wodgina district in Western Australia.

It was named from the Latin for antimony - STIBIum - in its composition, and its relation to tantalite.

Properties of Stibiotantalite

The following are the key properties of Stibiotantalite:

  • Cell Data
    • Space Group: Pc21n (synthetic SbTaO4)
    • a = 4.911
    • b = 11.814
    • c = 5.535
    • Z = 4

  • Crystal Data
    • Orthorhombic
    • Point Group: mm2
    • Crystals: prismatic (roman numeral two ) || [010], flattened (roman numeral two ) || to [001], may be equant, to 12cm; {001} and {101} striated (roman numeral two ) || [010]
    • Twinning: About [010] with composition plane {001}; polysynthetic
    • X-ray Powder Pattern: 3.121 (100), 3.506 (38), 2.950 (34), 2.687 (22), 2.692 (21), 1.735 (19), 1.888 (17)

  • Chemical Composition
    Elements Content 1 Content 2 Content 3
    Ta2O5 57.29 43.3 60.25
    Sb2O3 40.64 40.3 39.75
    Nb2O5 1.79 11.3 -
    Bi2O3 0.30 3.8 -
    SiO2 - 0.1 -
    CaO - 0.1 -
    Total 100.02 98.9 100.00

  • Optical Properties
    • Optical Class: Biaxial (+)
    • Orientation: X = a; Y = b; Z = c
    • Dispersion: r < v, strong
    • α = 2.374
    • β = 2.404
    • γ = 2.457
    • 2V(meas.) = n.d
    • 2V(calc.) = 75°5'

  • Estimated Properties
    Electron density Bulk density (electron density) = 6.44 g/cm3
    note: Specific gravity of Stibiotantalite = 7.57 g/cm3
    Photoelectric PEStibiotantalite = 711.98 barns/electron
    U = PEStibiotantalite x ρElectron density = 4585.80 barns/cm3
    Fermion index Fermion index = 0.0001
    Boson index = 0.9998
    Radioactivity
    Stibiotantalite is not radioactive

How to Identify Stibiotantalite

Stibiotantalite occurs in a range of colors, from brown to greenish-yellow, yellow, light yellow-brown, and dark brown. It has brittle fractures producing small, conchoidal fragments. The mineral is non-magnetic and non-fluorescent in nature. It has perfect cleavage, light yellow streak with adamantine luster, and transparent to translucent appearance.

The average density of stibiotantalite ranges from 6 to 7.4, and its hardness is 5.5.

Global Distribution

Stibiotantalite is distributed in the following places:

  • Greenbushes tin placers, Wodgina district, Western Australia
  • Muiˆane and other mines, Alto Ligonha, Mozambique
  • Benson mine, Mtoko, Zimbabwe
  • Topsham, Sagadahoc Co. Maine, USA
  • San Diego Co. California
  • Himalaya mine, Mesa Grande district, California
  • Katerina, Stewart, and Vandenburg mines, Pala district, California
  • Little Three mine, Ramona district, California
  • Brown Derby pegmatite, Gunnison Co. Colorado
  • Varutrask pegmatite, 15km north-west of Skelleftea, Vasterbotten, Sweden
  • Voronya massif, Kola Peninsula, Russia
  • Stak Nala, Gilgit district, Pakistan

Occurrence of Stibiotantalite and Useful Mineral Association

Stibiotantalite occurs as an uncommon accessory mineral in complex granite pegmatites.

It is closely associated with minerals like columbite–tantalite, cassiterite, alkalic beryl, lithiophilite, stibiomicrolite, microlite, allemontite, antimony, and tantalite.

References

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