Images
Formula: Ba2Mn3+(AsO4)2(OH)
Arsenate, brackebuschite supergroup,
manganese-bearing mineral
Crystal System: Monoclinic
Specific gravity: 5.124 calculated
Hardness: 6 to 6½
Streak: Yellow–orange
Colour: Dark red–brown
Environments
Lombardoite is a relatively new mineral, approved in 2016 and to date (August 2022) reported only from the type
locality.
Localities
At the type locality, the Valletta mine, Vallone della Valletta, Canosio, Cuneo Province, Piedmont, Italy,
lombardoite was found on the mine dumps in
iron-manganese ore in
metaquartzites. It occurs as orange brown, subhedral crystals less
than 0.5 mm in size in thin masses. Well-formed crystals, typically platy tablets, are very rare.
The lombardoite, together with aldomarinoite is associated with
quartz, aegirine,
baryte, calcite,
hematite, muscovite and
manganese minerals such as
cryptomelane, braunite and
manganberzeliite
(MM 86.447–458).
Back to Minerals