What is "ikaite"

n. (context mineralogy English) A saline evaporite, consisting of hydrated calcium carbonate with the chemical formula calciumcarbonoxygen₃'''·'''6water, found in cold marine waters.

Ikaite is the mineral name for the hexahydrate of calcium carbonate, CaCO·6HO. Ikaite tends to form very steep or spiky pyramidal crystals, often radially arranged, of varied sizes from thumbnail size aggregates to gigantic salient spurs. It is only found in a metastable state, and decomposes rapidly by losing most of its water content once removed from near-freezing water. This 'melting mineral' is more commonly known through its pseudomorphs.