Yellow crystal group of the new and extremely rare mineral steinmetzite (IMA 2015-081, and published in 2017) from the type locality and only one of the two known localities: Hagendorf South Pegmatite, Bavaria, Germany. The specimen is from Dr. Christof Schäfer, who split a part of the holotype specimen. The sharp crystals (pseudomorph after phosphophyllite), shown by mindat, is a single specimen. All the others do not build this sharp pseudomorphosis. — Photo: David Hospital · CC BY-SA 4.0
Steinmetzite
A very rare zinc-iron phosphate from Germany's famous Hagendorf pegmatites.
Intro adapted from Wikipedia (CC BY-SA).
Steinmetzite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Zn₂Fe³⁺(PO₄)₂(OH)·3H₂O.
It crystallizes in the triclinic crystal system (space group P-1).
Key properties: specific gravity 2.96; White streak; optically biaxial.
IMA symbol Snm, IMA status: approved, named in 2015.
From a highly oxidized zone of a granitic pegmatite, formed by alteration and replacement of phosphophyllite by oxidation of iron and some replacement of zinc by iron.
It is found associated with Albite, apatite, chalcophanite, jahnsite, mitridatite, muscovite, quartz, wilhelmgümbelite, goethite, cryptomelane, amorphous Fe-rich phosphate.
The mineral was named to honor Hermann Steinmetz (1879-1964), curator of Mineralogy at the Munich museum Sammlung des Bayerischen Staates from 1923 to 1928.