Chalconatronite

Chalconatronite is a carbonate mineral and rare secondary copper mineral that contains copper, sodium, carbon, oxygen, and hydrogen, its chemical formula is Na2[Cu(CO3)2]·3H2O. Chalconatronite is partially soluble in water, and only decomposes, although chalconatronite is soluble while cold, in dilute acids. The name comes from the mineral's compounds, copper ("chalcos" in Greek) and natron, naturally forming sodium carbonate. The mineral is thought to be formed by water carrying alkali carbonates (possibly from soil) reacting with bronze. Similar minerals include malachite, azurite, and other copper carbonates. Chalconatronite has also been found and recorded in Australia, Germany, and Colorado.