Cobaltoblödite

Cobaltoblödite is a rare cobalt mineral with the formula Na2Co(SO4)2·4H2O.[1][2] Cobaltoblödite was found in the Blue Lizard mine, San Juan County, Utah, USA, which is known for secondary uranium minerals.[3] Cobaltoblödite occurs intimately intergrown with manganese-, cobalt- and nickel-enriched blödite and a yet another new mineral - manganoblödite. Cobaltoblödite, as suggested by its name is a cobalt-analogue of blödite. It is also analogous to changoite, manganoblödite and nickelblödite - other members of the blödite group.[2]

Cobaltoblödite
General
CategorySulfate mineral
Formula
(repeating unit)		Na2Co(SO4)2·4H2O
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/a
Unit cella = 11.15, b = 8.27,
c = 5.54 [Å], β=100.52° (approximated); Z = 2
Identification
ColorColorless (grains), reddish-pink (aggregates)
Crystal habitAnhedral grains, in aggregates, forming crusts
CleavageNone
FractureUneven
Mohs scale hardness2.5
LusterVitreous
StreakWhite
DiaphaneityTransparent
Specific gravity2.29 (measured), 2.35 (calculated) (approximated)
Optical propertiesBiaxal (-)
Refractive indexnα=1.50, nβ=1.50, nγ=1.51 (approximated)
References[1][2]

Notes on chemistry

Manganoblödite is impure, containing admixtures of magnesium, manganese and nickel.[1]

Association and origin

Besite blödite and cobaltoblödite, other minerals associated with manganoblödite include chalcanthite, gypsum, johannite, sideronatrite, a feldspar group-mineral and quartz.[1]

References
  1. Kasatkin, A.V., Nestola, F., Plášil, J., Marty, J., Belakovskiy, D.I., Agakhanov, A.A., Mills, S.J., Pedron, D., Lanza, A., Favaro, M., Bianchin, S., Lykova, I.S., Goliáš, V., and Birch, W.D., 2013. Manganoblödite, Na2Mn(SO4)2·4H2O, and cobaltoblödite, Na2Co(SO4)2·4H2O: two new members of the blödite group from the Blue Lizard mine, San Juan County, Utah, USA. Mineralogical Magazine 77(3), 367-383
  2. "Cobaltoblödite: Cobaltoblödite mineral information and data". Mindat.org. Retrieved 2016-03-11.
  3. "Blue Lizard Mine, Chocolate Drop, Red Canyon, White Canyon District, San Juan Co., Utah, USA - Mindat.org". Mindat.org. Retrieved 2016-03-10.


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