STIBIOTANTALITE

    Class : Oxides and hydroxides
    Subclass : Oxides
    Crystal system : Orthorhombic
    Chemistry : SbTaO4
    Rarity : Rare


Stibiotantalite is an oxide of granitic pegmatites, very occasionally accompanying columbite, tantalite, beryl, elbaite and/or cassiterite. Its name reflects its antimony content and its similarity to tantalite. Stibiotantalite forms crystals of varied habits : prismatic, equant, thin or thick tabular, strongly striated according to elongation and frequently presenting polysynthetic twins. It is a mineral of quite variable color but remaining in the yellow to brown tones, which can go up to dark brown and black. It is a mineral of high density (nearly 7.4).


Main photo : Stibiotantalite from Himalaya Mine, California, USA © Rob Lavinsky

Stibiotantalite from Muiane, Mozambique © Jordy Fabre
Stibiotantalite from Himalaya Mine, California, USA © Rob Lavinsky
Twinned stibiotantalite from Mawi pegmatite, Afghanistan © Chris Stefano
Stibiotantalite from Himalaya Mine, California, USA © Rock Currier

Stibiotantalite in the World

Very beautiful crystals of stibiotantalite, exceeding 10 cm, are known from the Muiâne pegmatites (Mozambique), they are associated with morganite, rubellite, and manganotantalite. Magnificent tabular crystals have been extracted from the lithiniferous rubellite and lepidolite pegmatites of California, notably those of Pala and Mesa Grande. Superb yellow gem crystals are also reported in Afghan pegmatites. Stibiotantalite is particularly abundant associated with tantalite in the gigantic lithium pegmatite of Greenbushed (Australia). In Europe, it is known in the pegmatites of Varuträsk (Sweden) and in the Keivy massif in the Kola Peninsula (Russia).

Stibiotantalite in France

Stibiotantalite is not present in the French underground.

Twinning

Polysynthetic twins are known with axis [010] and composition plane {001}.

Fakes and treatments

No fakes listed for this mineral species.



Hardness : 5.5
Density : 7.34
Fracture : Sub-conchoidal
Streak : Light yellow to light brown


TP : Translucent to transparent
RI : 2.374 to 2.457
Birefringence : 0.083
Optical character : Biaxial +
Pleochroism : Visible
Fluorescence : None


Solubility : Hydrofluoric acid

Magnetism : NoneRadioactivity : None