This metal has not yet been met with in its native state, but is contained in certain ores of zinc, and especially in the black fibrous blends of Bohemia, which contains about five per cent. of it. It was discovered by M. Stromeyer in 1817, who used the following process for separating it from its ore. He dissolved it in dilute sulphuric or muriatic acid, and, after adding a portion of free acid, transmitted a current of sulphuretted hydrogen gas through the liquid, by which means the cadmium was precipitated as sulphuret, while the zinc remained in solution. The sulphuret of cadmium was then decomposed by nitric acid, and the solution evaporated to dryness; then the dry nitrate of cadmium was dissolved in water, and an excess of carbonate of ammonia added. The white carbonate of cadmium subsides, which, when heated to redness, yielded a pure oxide, and by mixing this oxide with charcoal, and exposing it to a further heat, metallic cadmium was obtained in the form of sublimation. Dr Wollaston's process is somewhat more simple; he placed the solution of the mixed metals in a platinum capsule along with a piece of metallic zinc. If cadmium be present it is reduced, and adheres to the capsule, after which it may be dissolved, either by nitric or dilute muriatic acid.

The cadmium thus obtained has in colour and lustre a strong resemblance to tin, but is somewhat harder and more tenacious. It is very ductile and malleable; melts at about the same temperature as tin, but is nearly as volatile as mercury; condensing like it into globules which have a metallic lustre. When heated in the open air it absorbs oxygen, and is converted into an orange-coloured oxide. It is readily dissolved by nitric acid, but is less easily acted upon by sulphuric and muriatic acids. Its specific gravity is 8-62.