Images
Formula: Na2Mn(SO4)2.4H2O
Hydrated sulphate, blödite group,
manganese-bearing mineral
Crystal System: Monoclinic
Specific gravity: 2.29 measured, 2.347 calculated
Hardness: 2½
Streak: White
Colour: Reddish pink in aggregates
Luminescence: Not fluorescent under UV or cathode rays
Environments
Sedimentary environments
Hydrothermal environments
Manganoblödite is a relatively new mineral, approved in 2012.
Localities
At the Womobi Mine, Thologolong, Towong Shire, Victoria, Australia, after the type locality a second occurrence of
manganoblödite was recognised at the abandoned Womobi mine, amongst an assemblage of post-mine
manganese sulphates forming encrustations on the wall of an adit. Here,
the manganoblödite forms blocky pale pink crystals up to 60 microns on edge, associated with
szmikite that has replaced
jokokuite
(MM 77.3.367-383).
At the type locality, the Blue Lizard Mine, Red Canyon Mining District, San Juan County, Utah, USA, specimens
containing both manganoblödite and cobaltoblödite were
collected underground. The mineralised channels were found in interconnected
sandstone and
conglomerate bodies that formed in braided stream
environments. Ore minerals have been deposited as replacements of wood and other organic material and as
disseminations in enclosing sandstone.
The main ore minerals are uraninite in association with
pyrite, chalcopyrite,
bornite and covellite. After
working ceased in 1978, supergene oxidation of
primary ores in the wet underground environment of the mine
yielded different secondary minerals, mainly sulphates as
efflorescence crusts on the surfaces of mine walls.
Manganoblödite and cobaltoblödite are very rare and occur
as intimate intergrowths with Mn-Co-Ni-bearing blödite in direct
association with chalcanthite,
gypsum, johannite,
sideronatrite, quartz
and feldspar. Other minerals found in the proximity include
atacamite, baryte,
bornite, brochantite,
chalcopyrite, copiapite,
covellite, cyanotrichite,
ferrinatrite,
halotrichite,
metavoltine,
natrozippeite,
pseudojohannite, pyrite,
romerite, rhomboclase,
tamarugite, uraninite
and several uranyl sulphates.
Manganoblödite occurs as anhedral isometric grains up to 60 microns in size, whereas
cobaltoblödite shows a grain size up to 200 microns. Grains of
these two minerals are combined in aggregates and crusts covering areas of up to 2 x 2 cm2 on the
surface of other sulphates. In aggregates and crusts both minerals are intimately intergrown with each other and
with Mn-Co-Ni-bearing blödite. The three minerals cannot be distinguished
one from another by visual methods. Manganoblödite and
cobaltoblödite are transparent and colourless in single grains and
are reddish pink in aggregates and crusts, with a white streak and a vitreous lustre
(MM 77.3.367-383).
Manganoblödite from the Blue Lizard Mine -
Image
Back to Minerals