Columbite, also called niobite, niobite-tantalite and columbate [(Fe, Mn)Nb2O6], is a
black mineral group
that is an ore of niobium. It has a
submetallic luster and a high density and is a niobate of iron and manganese.
Detailed description
This mineral group was first found in Haddam, Connecticut, in the United States. It forms a series with the tantalum-dominant
analogue ferrotantalite and
one with the manganese-dominant analogue manganocolumbite. The
iron-rich member of the columbite group is ferrocolumbite. Some tin
and tungsten may be present in the mineral. Yttrocolumbite is
the yttrium-rich columbite with the formula (Y,U,Fe)(Nb,Ta)O4. It is
a radioactive mineral found in Mozambique.
Columbite has the same composition and crystal
symmetry (orthorhombic) as tantalite. In fact, the two are
often grouped together as a semi-singular mineral series called columbite-tantalite or coltan in
many mineral guides. However, tantalite has a much greater specific gravity than
columbite, more than 8.0 compared to columbite's 5.2.
Columbite is also very similar to tapiolite. Those minerals
have same chemical composition but different crystal symmetry: orthorhombic for
columbite and tetragonal for tapiolite. The largest
documented single crystal of columbite consisted of plates 6 mm
(0.24 in) thick measuring 76 cm × 61 cm (30 in
× 24 in).
PRICE
$41.5/KG
For more information:
mobile: +2348039721941
contact person: emeaba uche
e-mail: emeabau@yahoo.com
Comments
Post a Comment