Cadmium is named from the Latin cadmia, the ancient name for calamine, zinc carbonate and was first discovered in 1817. Cadmium most often occurs in small quantities associated with zinc ores, such as sphalerite. Greenockite is the only mineral of any consequence bearing cadmium. Almost all cadmium is obtained as a by-product of the treatment of lead, copper and zinc ores. Cadmium is a soft, bluish metal which is easily cut with a knife and is very similar in many respects to zinc. It is used in bearing alloys with low coefficients of friction and great resistance to fatigue; it is used for electroplating, which accounts for 60% of its use. Cadmium is also used in the production of nickel-cadmium batteries and is used in blue and green phosphors in color television tubes.