Ernstite Locality: Boa Esperança claim, Linópolis, Divino das Laranjeiras , Doce valley, Minas Gerais , Southeast Region, Brazil ( Locality at mindat.org ) Size: 4 x 2.8 x 2.7 cm. Ernstite pseudomorph after Childrenite The spear-like crystals of ernstite, a rare manganese, iron, aluminum, phosphate, has a burnt umber appearance. Ex. Martin Zinn Collection. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Ernstite
Ernstite is an IMA-recognized mineral species in the phosphate class, with the chemical formula (Mn²⁺,Fe³⁺)Al(PO₄)(OH,O)₂.
It crystallizes in the orthorhombic crystal system (space group Bbam). It is a member of the Childrenite structural group.
Key properties: Mohs hardness 3–3.5; specific gravity 3.07; optically biaxial.
IMA symbol Ens, IMA status: approved, named in 1970.
produced through oxidation of eosphorite in a granite pegmatite (Farm Davib-East, Namibia).
It is found associated with Eosphorite (Farm Davib-East, Namibia).
The mineral was named to honor Dr. Theodor K.H. Ernst (1904–1983), Professor of Mineralogy, Erlangen University, Erlangen, Germany.