ikaites

Ikaite is a hydrated calcium carbonate mineral with the chemical formula CaCO3·6H2O. It is also known as okenite, but this is an older and less common name. Ikaite is metastable at room temperature and pressure, meaning it readily decomposes into calcite, water, and carbon dioxide when warmed. This decomposition is why ikaites are rarely found in surface environments.

The mineral is typically found in cold, aqueous environments, such as the deep sea, glacial sediments, and within ice caves. It often forms as a result of the interaction between calcium-rich brines and dissolved carbon dioxide in cold water. The specific conditions required for its formation, particularly the low temperature and high dissolved CO2 concentration, make it a relatively rare mineral.

Ikaite crystals are usually colorless to white and can be prismatic or acicular in habit. They are relatively soft and easily scratched. Due to its metastability, the study of ikaites often requires specialized techniques to preserve their structure and composition. Despite its ephemeral nature, ikaites are of interest to geologists and chemists for understanding carbonate formation processes in cold environments and for their potential implications in paleoclimate research. The presence of ikaites can indicate past or present cold, carbon-rich aqueous conditions.