Borax-bearing minerals are used almost entirely in the manufacture of borax and boric acid. Fully a third of the borax consumed in the United States is used in the manufacture of enamels or porcelain-like coatings for such objects as bathtubs, kitchen sinks, and cooking utensils. Other uses of borax or of boric acid are as a flux in the melting and purification of the precious metals, in decomposing chromite, in making glass, as a preservative, as an antiseptic, and as a cleansing agent. Recent developments indicate that the metal, boron, may play an important part in the metallurgy of various metals. It has been used in making very pure copper castings for electrical purposes, in aluminum bronzes, and in hardening aluminum castings; and an alloy, ferroboron, has been shown experimentally to act on steel somewhat like ferrovanadium. The bulk of the world's borax comes from the Western Hemisphere, the United States and Chile being the two principal producers. There are additional large deposits in northern Argentina, southern Peru, and southern Bolivia, which have thus far been little drawn on because of their inaccessibility. English financial interests control most of these South American deposits. The only large European producer of borax is Turkey. Italy and Germany produce small amounts. There has also been small production of borax in Thibet, brought out from the mountains on sheep-back. The United States supplies of borax are sufficient for all domestic requirements and probably for export. Small quantities of boric acid are imported, but no borax in recent years. The domestic production comes entirely from California, though in the past deposits in Nevada and Oregon have also been worked. GEOLOGIC FEATURES The element boron is present in various complex boro-silicates, such as datolite and tourmaline, the latter of which is used as a precious stone (pp. 290, 293). None of these are commercial sources of borax. The principal boron minerals are borax or "tincal" (hydrated sodium borate), colemanite (hydrated calcium borate), ulexite (hydrated calcium-sodium borate), and boracite (magnesium chloro-borate). Commercially the term borax is sometimes applied to all these materials. These minerals appear in nature under rather widely differing modes of origin. The borax production of Italy is obtained from the famous "soffioni" or "fumaroles" of Tuscany. These are volcanic exhalations, in which jets of steam carrying boric acid and various borates, together with ammonium compounds, emerge from vents in the ground. The boric acid material is recovered by a process of condensation.