VII. Class of Minerals

Nitrates are natural salts of nitric (nitrogen) acid. They have similar crystallographic characteristics to carbonates, as both contain a characteristic planar, triangular anion group formed by a nitrogen atom strongly bonded to three oxygen atoms. Nitrates are very rare in nature due to their high solubility in water and are found only in extremely dry areas, such as the Atacama Desert, where the largest nitrate deposits in the world are located. The most famous minerals from the nitrate class are saltpeter (potassium nitrate) and Chilean saltpeter (sodium nitrate), which dominate the nitrate deposits in the Atacama Desert.