They may be recognized by the brownish violet colour they impart to a borax bead when heated in an oxidizing flame.
The same hydrate can be prepared by dissolving borax in water until the solution has a specific gravity of 1.246 and then allowing the solution to cool.
In 1927 a very large deposit of relatively pure Borax was discovered at what is now Boron, CA, in the Mojave Desert.
In borax (of which California's output in 1904 was 45,647 tons) and structural materials San Bernardino has a long lead.
Sulphur deposits exist in the Sechura desert region, on the coast, and extensive borax deposits have been developed in the department of Arequipa.
Like the other provinces of this region, Antofagasta produces for export copper, silver, silver ores, lead, nitrate of soda, borax and salt.
The nitrate and borax deposits are extensive and productive, and common salt is a natural product of large areas in the elevated desert regions of the Andes.
The precipitate is collected in a filter-press, and then roasted in muffle furnaces with nitre, borax and sodium carbonate.
Boric acid only belongs partially to this group, as it and its compound borax have certain specific actions in addition.
The supply of borax is, however, mainly derived from the boric acid of Tuscany, which is fused in a reverberatory furnace with half its weight of sodium carbonate, and the mass after cooling is extracted with warm water.