'Monohydrocalcite' is a mineral that is a hydrous form of
calcium carbonate, CaCO
3.H
2O.
It is a
trigonal mineral which is white when pure. Monnohydrocalcite is not a common rock-forming mineral, but is
frequently associated with other calcium and magnesium
carbonate minerals, such as
calcite,
aragonite,
lansfordite and
nesquehonite.
Monohydrocalcite has been observed in air conditioning systems, and as a deposit in caves, both probably formed from spray of carbonate rich fluids.
It is well-known in the Robe district of
South Australia as a component of beach sands of Lake Fellmongery and Lake Butler,
where it is believed to be an
evaporite. It has been reported as a significant component of the decomposition of
ikaite
in the towers of the Ikka Fjord. It is also noted for its bizarre occurrences, which include inside the
otoliths of the
tiger shark,
the
bladder of a
guinea pig, the
skull of an extinct
cave bear, and the putrefying flesh of the giant
saguaro cactus. These occurrences suggest
a biochemical origin is possible.
Further Reading
★ Catherine, H., Skinner, K., Osbaldiston, G. W., Wilner, A. N. Monohydrocalcite in a guinea pig bladder stone, a novel occurrence. American Mineralogist, 62: 273 - 277, 1977.
★ Dahl, K., Buchardt B. Monohydrocalcite in the arctic Ikka Fjord, SW Greenland:First reported marine occurrence. Journal of Sedimentary Research, 2006, vol. 76. DOI: 10.2110/jsr.2006.035
★ Garvie, L.A.J. Decay-induced biomineralization of the saguaro cactus (Carnegiea gigantea) American Mineralogist, 88: 1879-1888, 2003
★ Hull, H., Turnbull, A. G. A thermochemical study of monohydrocalcite. Geochimica et Cosmochimica Acta, 37: 685-694, 1973
External Links
★
Webmineral
★
Mindat