Glendonite-Glendoniet

Ikaite incorporates water molecules while crystallizing, and can only form in very cold temperatures. When the matrix, usually a silaceous mud, encasing the ikaite crystals warms, as a result of ground movement or climate change, the Ikaite crystals collapse back into an aqueous solution, which then over time re-crystallizes as calcite, filling the void left by the collapsed Ikaite and reproducing its form pseudomorphically. Cool huh!