As a rare secondary mineral in the oxidized zone of bismuth- and arsenic-bearing mineral deposits.
IMA Status:
Valid Species (Pre-IMA) 1832
Locality:
In Germany, in Saxony, at the Neuhilfe, the Weisser Hirsch, and the Junge Kalbe mines, Neustadtel-Schneeberg; from Gadernheim, near Bensheim, Hesse; and the Neubulach and the Schmiedes
Link to MinDat.org Location Data.
Name Origin:
Derivation not explicitly stated. Probably from the Greek for "incomplete," as the composition was undetermined when the mineral was first described.
Chemical Formula: 