TANTALITE
Specimen tnt-3
$ 48.00Dims: 1.5" x 0.8" x 0.5" (3.8 x 2.0 x 1.3 cm)
Wt: 14.9 g
Quixaba Mine, Frei Martinho, Paraiba, Brazil
This small thumbnail specimen consists of at least 4 Manganotantalite crystals that are embedded in a pegmatite base. These crystals are in moderately good condition, as the largest one is obviously damaged and missing part of its termination. This largest crystal has visible dimensions of 0.8 x 0.3 x 0.1" (2.0 x 0.8 x 0.3 cm), and like the others, shows a warped but definite orthorhombic prismatic form and a pearly luster. It has a brownish-red coloration and would likely be transparent if it was not so intensely internally-fractured; it is translucent at the least, though. Some of the crystals seem to show good form, but are almost completely covered by the base rock, which protected them. As the base rock does not react to concentrated HCl, I am rather certain that it consists almost entirely of a feldspar.