Reddish brown crystal aggregates of the extremely rare arsenate ogdensburgite from the type locality in Ogdensburg and only one of the four known localities worldwide: Sterling Hill, Ogdensburg, Sussex County, New Jersey, United States of America. Find from 1982 in the Sohle 340 of the Sterling Hill mine. Ex Vandenbroucke Museum collection specimen, from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Ogdensburgite
Ogdensburgite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Ca₂Fe³⁺₄Zn(AsO₄)₄(OH)₆·6H₂O.
It crystallizes in the orthorhombic crystal system.
Key properties: Mohs hardness 2; specific gravity 3.11; Pale orange streak; Resinous on cleavages luster; optically biaxial.
IMA symbol Obu, IMA status: approved, named in 1980.
On oxidized ore from a metamorphosed stratiform zinc orebody (Sterling Hill, New Jersey, USA); in oxidized ore from an arsenic-rich polymetallic hydrothermal ore deposit (Ojuela mine, Mexico).
It is found associated with Parasymplesite, köttigite, yukonite, legrandite, pharmacosiderite, willemite, franklinite, sphalerite (Sterling Hill, New Jersey, USA); villyaellenite.
The name refers to its occurrence at Ogdensburg, New Jersey, USA.