Rutile, v. Struverite-Ilmenorutile
Posted by: macadmin on 05.14.2020 | Filed under:

Rutile, v. Struverite-Ilmenorutile

Specimen # 101423
Mineral: Rutile, v. Struverite-Ilmenorutile
Location: Rutile, var. Struverite-Ilmenorutile, Golconda District, Governador Valadares, Minas Gerais, Brazil
Size: 4.1 x 2.8 x 1.8 cm


This is one of the finest crystals of this variety of rutile I have ever seen. It is sharp and lustrous, and it exhibits both parallel-growth and contact twinning. I acquired this specimen from Luiz Menezes for my own collection, in 2011. Luiz bought them from a seller who had labeled them tantalite, and, as Luiz so often was, he was skeptical of the identification, and he had analysis done. The specimens from this small find were determined to be rutile, containing Ta:Nb ratios that varied, so that some parts of the crystals are struverite, some are ilmenorutile, and some parts have ratios of 1:1. This crystal is doubly-terminated, and the bottom termination (as I’d display it) of the large crystal is a more frosted lustre, having grown against the matrix. In excellent condition, a chip on each downward facing termination and a cople of tiny inconsequential ones elswhere. Luiz was not certain about the transparent crystals lodged in the top and one side of this specimen – seems either aquamarine or topaz, but we agreed hard to tell – needs a little work to know. Those crystals are undamaged, the top one shows some etching.

The pegmatite of origin was described to Luiz as unnamed, excavated in October 2010.

A fantasitc specimen of rutile var. stuverite/ilmenorutile.

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Additional information

Dimensions 48 × 28 × 18 cm