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Formula: Ni(SO4).7H2O
Hydrated normal sulphate, epsomite group, forms a complete series with
epsomite, nickel-bearing mineral
Crystal System: Orthorhombic
Specific gravity: 1.953 measured, 1.93 calculated
Hardness: 2 to 2½
Streak: White, faint green tint
Colour: Apple green or greenish white, green in transmitted light
Common impurities: Fe
Environments
Morenosite is an uncommon secondary mineral in the
oxidised zone of nickel-bearing hydrothermal mineral deposits, formed from
H2O solution below 31.5oC. Associated minerals include
retgersite,
nickelhexahydrite,
annabergite
and millerite
(HOM).
Localities
At Marbridge Mine, La Motte, Abitibi RCM, Abitibi-Témiscamingue, Quebec, Canada, morenosite is found coating
millerite
(Dana).
At Malenco Valley, Sondrio Province, Lombardy, Italy, morenosite is associated with
retgersite
(Dana).
At the Ragra mine (Minasragra), Huayllay District, Pasco Province, Pasco, Peru, morenosite has been found
associated with minasragrite and
retgersite
on a specimen of patronite
(AM 34.188-194).
At the type locality, the Manolita mine, Teixidelo, Cedeira, A Coruña, Galicia, Spain, morenosite commonly
occurs as fibrous or fine-grained efflorescences and contains hydrous impurities, notably
annabergite
(AM 34.188-194).
At Gordon's Quarry, Kaukapakapa, Auckland Region, North Island, New Zealand, morenosite is found as
efflorescent patches on freshly broken surfaces of
serpentinite. The host rock is a
serpentinite of the
dunite
type enclosing scattered grains of pentlandite-bearing
pyrrhotite, and it is on these that morenosite has crystallised.
In the same quarry epsomite also occurs at other points on the
serpentinite surface. The close association of the
morenosite and epsomite with
pyrrhotite suggests that
the pyrrhotite was a factor in their formation. Oxidation of
pyrrhotite gives ferric sulphate and sulphuric acid; the sulphuric
acid so derived reacts with the readily soluble serpentinite
and with the pentlandite in the
pyrrhotite,
giving sulphates of nickel, magnesium, and
iron
(AM 32.553-560).
Alteration
Morenosite dehydrates to retgersite
Ni(SO4).7H2O → Ni(SO4).6H2O + H2O
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