Nahcolite

Nahcolite is a soft, colourless or white carbonate mineral with the composition of sodium bicarbonate (NaHCO₃) also called thermokalite. It crystallizes in the monoclinic system.

Nahcolite was first described in 1928 for an occurrence in a lava tunnel at Mount Vesuvius, Italy. Its name refers to the elements which compose it: Na, H, C, and O. It occurs as a hot spring and saline lake precipitate or efflorescence; in differentiated alkalic massifs; in fluid inclusions as a daughter mineral phase and in evaporite deposits.