Borax (hydrous sodium borate) occurs in nature in an impure form and is prepared also from calcium borates. Borates are found in Tuscany, Central Asia, California and Nevada, and in South America.
Borax and boracic acid are used in pottery manufacture, for the preservation of meat, in dyeing and in medicine.
Strontium is found in Germany, Scotland, Texas and New York. Strontianite (strontium carbonate) and celestite (strontium sulphate) contain this element. Strontium salts are used in sugar refining and making red fire.
Sulphur or brimstone is found in a pure state in volcanic regions or associated with gypsum and limestone. Pyrite (sulphide of iron) is also a source of sulphur compounds.
Sicily, Italy, Japan, Louisiana and Utah have mines of native sulphur, which is used in manufacturing sulphuric acid, gunpowder, matches, as a disinfectant, for bleaching and vulcanizing rubber.
Blue vitriol, green vitriol and alum are sulphates. Sulphur is imported from Sicily and Italy.
Thorium. See [rare metals].
Tin is less abundant than most of the common metals. The Malay peninsula and nearby islands (Banca and Billiton) produce over half the tin ore of the world. The remainder is mined in Bolivia, Australia, Tasmania and Cornwall, England. Small deposits occur in the United States.
Tin melts at a low temperature and is easily refined.
Cassiterite (tin oxide) is the only important ore. This mineral is commonly found as pebbles (stream tin) in gravel.