Tantalite Value, Price, and Jewelry Information


Tantalite
Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0], via Wikimedia Commons

Tantalite is too dark to be of use as a faceted gem but is sometimes cut as a collector curiosity, either faceted or in cabochons. These could be of any desired size.

Tantalite Value

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Tantalite Information

DataValue
NameTantalite
VarietiesManganotantalite
Crystallography Orthorhombic. Crystals tabular prismatic, in aggregates, massive, compact.
Colors Black, brownish black, reddish brown; may tarnish iridescent.
Luster Submetallic to vitreous.
Fracture Uneven. Brittle.
Hardness 6-6.5.
Specific Gravity 8.2; decreases with Ta content (columbite, 5.2).
Birefringence 0.160.
Cleavage Distinct 1 direction.
Stone SizesVery large crystals weighing many pounds have been found. The material is usually dark colored, opaque, and of interest only for cabochons.
Luminescence None.
Formula(Fe,Mn)(Nb,Ta)2O6.
Pleochroism Strong; brown/red-brown.

TANTALITE Series to Columbite: (Fe,Mn)(Nb,Ta)2O6.

Streak: Black, brownish black, reddish brown.

Optics: a= 2.26; β= 2.30-2.40; γ=2.43.

Biaxial (+), 2VLarge. Usually opaque, indices measured on powders or thin splinters

Spectral: Not diagnostic.

Occurrence: In granite pegmatites.

Colorado; Wyoming; New England.

Canada; Brazil; Madagascar; France; Sweden: Finland; USSR; Zimbabwe; Western Australia.

South Dakota: various localities.

California: various localities.

Comments: Tantalite is too dark to be of use as a faceted gem but is sometimes cut as a collector curiosity, either faceted or in cabochons. These could be of any desired size.

Name: After the mythical character Tantalus, because it is difficult to dissolve the mineral in acids prior to analysis.