Manganotantalite Value, Price, and Jewelry Information


MANGANOTANTALITE: Alta Ligonha, Mozambique (5.5). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Manganotantalite makes a spectacular red brown gem that is a very rare collector’s item. Transparent material is light enough in color to allow lots of light to enter and leave a cut gem, and properly cut stones are lively and brilliant. Cutting is difficult because of the cleavage.

Manganotantalite Value

The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.

Manganotantalite Information

DataValue
NameManganotantalite
Is a Variety ofTantalite
Crystallography Orthorhombic. Crystals short prismatic; massive.
Refractive Index 2.19-2.34
Colors Brownish black, reddish brown, scarlet red.
Luster Vitreous to resinous.
Fracture Subconchoidal to uneven
Hardness 5.5-6.5.
Specific Gravity Mozambique material: 7.73-7.97.
Birefringence 0.150
Cleavage Distinct 1 direction
Dispersion High.
Stone SizesCuttable crystals seldom reach 1 inch in size, and gems over 10 carats are rarities. However, the material is so dense that even a small stone is relatively heavy. Devonian Group (Calgary, Alberta, Canada): 3.05 (red-brown, Brazil).
Luminescence None.
Transparency Transparent to opaque.
Absorption Spectrum Not diagnostic.
Formula(Mn,Fe)(Ta,Nb)2O6; Mn: Fe=3:1.
Pleochroism Shades of brown and red-brown. Also deep red/pale pink.
Optics α = 2.19; β = 2.25; γ = 2.34. Biaxial (+); 2large.

Series to Manganocolumbite;

Ferrotantalite; Columbotantalite.

Streak: Dark red.

Occurrence: In granite pegmatites; sometimes in placer deposits.

Pala, California; Portland, Connecticut; Amelia, Virginia.

Andilana, Madagascar; Sanarka River, Urals, USSR;

Sweden; Wodgina, Western Australia.

Minas Gerais, Brazil: facetable crystals.

Alta Ligonha, Mozambique: gem quality crystals. A150 from the Morrua Mine, Zambesia.

Comments: Manganotantalite makes a spectacular red brown gem that is a very rare collector’s item. Transparent material is light enough in color to allow lots of light to enter and leave a cut gem, and properly cut stones are lively and brilliant. Cutting is difficult because of the cleavage.

Name: After the composition, a manganiferous tantalite.