- Rutile (Var: Struverite)
- Samiresy, Sahatany Pegmatite Field (Mt Bity (Ibity) area), Vakinankaratra Region, Antananarivo Province, Madagascar
- Toenail, 3.1 x 3.1 x 1.8 cm
This rare earth oxide appears not to be a valid species anymore, but rather a variety of Rutile. It is closely related to Ilmenorutile, however the presence of Tantalum makes for a very unique chemistry. This piece features a very sharp, well formed, dark brownish-black crystal of "Struverite" measuring 1.0 cm on massive translucent Quartz matrix. These specimens are no longer being found.