Aeruginosa, chemical formula Cu2 (OH) 2CO3, also known as the main component of copper carbonate basic (impurities), is a rare mineral stone and a kind of salt.

It is a green rust reaction of oxygen, carbon dioxide and water, other substances in the air and copper coating, containing elements of copper, oxygen, hydrogen and carbon, also called patina. Heating in the air will break down into copper oxide, water, and carbon dioxide.

Aeruginosa is insoluble in water but soluble in acid. Its unstable character is easy to decompose when heated. With hydrochloric acid, the sodium carbonate solution is added to the copper salt, available copper carbonate precipitation. Copper Carbonate Basic can be used for pigment, insecticidal sterilization agent and flare etc. Patina is also a traditional Chinese medicine.