Pelouze. Ikaite is only thermodynamically stable at moderate pressures, so when found near the Earth's surface is always metastable. Nevertheless, as it appears to be at least moderately common in nature, it is clear that the conditions for metastable nucleation and growth cannot be too restrictive. Cold water is certainly required for formation, and nucleation inhibitors like phosphate ions for the growth of anhydrous calcium carbonate phases, such as calcite, aragonite, and vaterite probably aid its formation and preservation. It is thought that perhaps the structure of calcium carbonate in a concentrated aqueous solution also consists of an ion pair, and that this is why ikaite readily nucleates at low temperatures, outside of its thermodynamic stability range. When removed from its natural cold water environment, ikaite rapidly disintegrates into monohydrocalcite or anhydrous calcium carbonate phases and water, earning the nickname of the melting mineral. Pseudomorphs The presence of ikaite may be recorded through geological time through the presence of pseudomorphs of other calcium carbonate phases after it. Although it can be hard to uniquely define the original mineral for every specimen, there appears to be good evidence for ikaite as the precursor for the majority of the following locality names of pseudomorphs: Glendonite, after type locality, Glendon, New South Wales, Australia. Thinolite, (Gr. Thinos = shore) found in the tufa of Mono Lake, California, US Jarrowite, Jarrow, Northumberland, UK Fundylite, Bay of Fundy, Nova Scotia, Canada Gersternkorner, (Ger. = Barleycorn) Gennoishi, (Jp. = hammerstones) Molekryds, (Dan. = Mole Cross), Mors Island, Jutland, Denmark Pseudogaylussite (from semblance to Gaylussite) White Sea hornlets, White Sea and Kola peninsula. Ikaite or its pseudomorphs have been reported as occurring in marine, freshwater, and estuarine environments. The common ingredient appears to be cold temperatures, although the presence of traces of other chemicals such as nucleation inhibitors for anhydrous calcium carbonate may also be required. It has also been reported as forming in winter on Hokkaido at a saline spring. Since cold water can be found at depth in the oceans even in the tropics, ikaite can form at all latitudes. However, the presence of ikaite pseudomorphs can be used as a paleoclimate proxy or paleothermometry representing water near freezing conditions. Thinolite deposits Thinolite is an unusual form of calcium carbonate found on the shore (Greek: thinos = shore) of Mono Lake, California. This and other lakes now largely in the desert or semi-desert environments of