Zemannite Locality: Moctezuma Mine (Bambolla Mine), Moctezuma , Municipio de Moctezuma , Sonora , Mexico ( Locality at mindat.org ) Picture width 2 mm. Collection and photograph Christian Rewitzer — Photo: Christian Rewitzer · CC BY-SA 3.0
Zemannite
A very rare hexagonal magnesium-zinc-iron tellurite forming small brown prisms.
Intro adapted from Wikipedia (CC BY-SA).
Zemannite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Mg₀.₅ZnFe³⁺(Te⁴⁺O₃)₃·nH₂O (3≤n≤4.5).
It crystallizes in the hexagonal crystal system (space group P6_3/m). It is a member of the Zemannite structural group.
Key properties: specific gravity 4.19; White streak; Adamantine luster; optically uniaxial.
IMA symbol Zem, IMA status: approved, named in 1968.
A rare secondary mineral found in the oxidized zone of a hydrothermal Au–Te deposit.
It is found associated with Tellurium, tellurite, paratellurite, spiroffite, mroseite.
The mineral was named to honor Dr. Josef Zemann (1923–), Austrian crystallographer, Professor of Mineralogy, University of Vienna, Vienna, Austria, specialist in tellurium minerals.