Henritermierite Locality: Wessels Mine (Wessel's Mine), Hotazel, Kalahari manganese fields, Northern Cape Province , South Africa ( Locality at mindat.org ) Size: 4.5 x 4 x 3 cm. An extremely fine specimen of this very rare species. Not only do you have a large dominant crystal on a rich matrix, but the lustre is so sharp and bright that at first glance you might think this is a magnetite from Switzerland. Ex. Charlie Key. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Henritermierite
Henritermierite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₃Mn³⁺₂(SiO₄)₂(OH)₄.
It crystallizes in the tetragonal crystal system (space group I4_1/acd). It is a member of the Garnet structural group.
Key properties: specific gravity 3.34; White streak; Vitreous luster; optically uniaxial.
IMA symbol Hri, IMA status: approved, named in 1968.
Occurs as small grains filling interstices between crystals of other minerals in a manganese ore deposit (Tachgagalt mine, Morocco).
It is found associated with Marokite, hausmannite, gaudefroyite, calcite (Tachgagalt mine, Morocco); hausmannite, manganite, hematite, calcite, barite, andradite (N'Chwaning mine.
The name refers to Henri F.E. Termier (1897{), Professor of Geology at the Sorbonne, Paris, France.