Calcite

Calcite is a form of calcium carbonate (CaCO3). Like calcite, minerals including aragonite, chalk, limestone, and marble are also forms of calcium carbonate.

The caves found on Xantoras consisted of calcite, aragonite, and botyroidal flowstones. 

After reaching a dead-end while hiding in the caverns from the Son'a on the Ba'ku planet, Data noted that there was oxygen-nitrogen atmosphere behind the calcite formation he was scanning.