A nitrate mineral having chemical composition NaNO₃ (sodium nitrate). Soda niter, otherwise known as nitratite, is by far the most abundant of the nitrate minerals. It crystallizes in the rhombohedral division of the hexagonal system. It sometimes occurs as simple rhombohedral crystals but is usually massive granular. The mineral has a perfect rhombohedral cleavage, conchoidal fracture, and is rather sectile. Its hardness is 1.5 to 2 on Mohs scale, and its specific gravity is 2.266. It has a vitreous luster and is transparent. It is colorless to white, but when tinted by impurities, it is reddish brown, gray, or lemon yellow.