Stannite The name comes from the Latin for tin: "stannum". It was first described in 1797 for an occurrence in Wheal Rock, St. Agnes, Cornwall, England. Stannite Stannite is a mineral, a sulfide of copper, iron, and tin. The chemical formula CuFeSnS. Zinc commonly occurs with the iron and trace germanium may be present. Stannite is used as an ore of tin, consisting of approximately 28% tin, 13% iron, 30% copper, 30% sulfur by mass. It is found in tin-bearing, hydrothermal vein deposits occurring with chalcopyrite, sphalerite, tetrahedrite, arsenopyrite, pyrite, cassiterite, and wolframite. It is also known as "bell metal ore"
Alkali metal obtained the same way: sulfuric acid is first used to dissolve the desired alkali metal ion and aluminium(III) ions from the ore (leaching), whereupon basic precipitation removes aluminium ions from the mixture by precipitating it as the hydroxide. The remaining insoluble alkali metal carbonate is then precipitated selectively; the salt is then dissolved in hydrochloric acid to produce the chloride. The result is then left to evaporate and the alkali metal can then be isolated. Lithium and sodium are typically isolated through electrolysis from their liquid chlorides, with calcium chloride typically added to lower the melting point of the mixture.