Sodium amalgam sodium metal in mercury or the reverse. Sodium amalgams can be purchased from chemical supply houses. Since its introduction in the 1880s by students of Robert Bunsen, Julius Tafel and Hans Goldschmidt, sodium amalgam has also been used in organic chemistry as a powerful reducing agent, which is safer to handle than sodium itself. An example of its use is in the Emde degradation. A sodium amalgam is used in the design of the high pressure sodium lamp providing sodium to produce the proper color, and mercury to tailor the electrical characteristics of the lamp. Sodium amalgam is a by-product
Amalgam tattoo from pencil leads), and is sometimes termed a "graphite tattoo", although this is less common than tattooing with amalgam. The diagnosis is clinical. Amalgam tattoo can be distinguished from other causes of localized oral pigmentation because it does not change significantly in size or color, although it may appear to slowly enlarge for several months after the initial implantation of the metal particles. Some amalgam tattoos appear radio-opaque on radiographs (i.e. they show up on x-rays), although in many cases amalgam tattoos have no radiographic features since the responsible particle(s) of amalgam are very small even though clinically the area