Coronadite - Encyclopedia

    Class : Oxides and hydroxides
    Subclass : Oxides
    Crystal system : Monoclinic
    Chemistry : PbMn₈O₁₆
    Rarity : Uncommon

Coronadite is an oxide of manganese and lead, sometimes slightly hydrated, frequently showing low iron and aluminum contents. It is a secondary mineral which forms in the upper oxidized part of lead and manganese deposits, perhaps by recrystallization of a lead-bearing psilomelane. It takes its name from its place of discovery : the Coronado vein (Arizona, USA). It is usually massive, constituting botryoidal or nipple-like masses with a fibrous or fibrolamellar texture, with a surface commonly bristling with small crystalline points. Its color is light gray to black, with a semi-metallic to dull luster ; it is distinguished from other manganese oxides by its high density (nearly 5). It is occasionally an ore of manganese and lead.

Main photo : Coronadite from Rosh Pinah Mine, Ilkaras Region, Namibia © Bruce Cairncross

No twin known for this mineral species.

No fake identified for this mineral species but can be difficult to differentiate from the psilomelane with which it shares its deposits.