Lithium be cut with a knife. When cut, it possesses a silvery-white color that quickly changes to gray as it oxidizes to lithium oxide. While it has one of the lowest melting points among all metals (180 °C), it has the highest melting and boiling points of the alkali metals. Lithium has a very low density (0.534 g/cm), comparable with pine wood. It is the least dense of all elements that are solids at room temperature; the next lightest solid element (potassium, at 0.862 g/cm) is more than 60% denser. Furthermore, apart from helium and hydrogen, it is less dense than
Least bittern Least bittern The least bittern ("Ixobrychus exilis") is a small heron, the smallest member of the family Ardeidae found in the Americas. The least bittern is one of the smallest herons in the world, with perhaps only the dwarf bittern and the black-backed bittern averaging smaller in length. It can measure from in length, and the wingspan ranges from . Body mass is from , with most least bitterns weighing between , making this perhaps the lightest of all herons. A recent manual of avian body masses cites another species in this genus, the stripe-backed bittern, as having a mean