tincal

Tincal is borax in its raw, unrefined state: sodium tetraborate decahydrate crystallized from evaporated lake beds, white and slightly waxy to the touch. The richest natural deposits lay on the Tibetan plateau, where dry alpine lakes left mineral crusts that traders collected and carried south and west. Sanskrit physicians knew it as tankana by the first century CE, listing it as a flux for metalworking and a remedy for respiratory ailments. The trade in raw borax from Tibet was already well established when the Silk Road reached its medieval peak.

The Arabic word tinkār appears in ninth-century chemical treatises by Jābir ibn Hayyān, known in Latin Europe as Geber, who described its value for soldering gold and silver. Arabic merchants moved tincal westward from Central Asia while Malay traders moved it eastward; the Malay form tingkal appears in fifteenth-century trade inventories from Malacca. The Portuguese, arriving in Malacca in 1511, heard tingkal and brought both the mineral and its name home as atincar.

By 1600 English glassmakers and goldsmiths were importing tincal from India via Portuguese and Dutch middlemen, and the word had settled into its English form. Its use as a flux lowered the melting point of metals and glass, making it indispensable in European workshops before synthetic borax became available. The Royal Society's 1665 Philosophical Transactions described tincal shipments from Bombay, noting the crystalline crust and the white powder left after refining.

The California borax rushes of the 1870s made 'borax' the commercial standard in English, displacing tincal from trade language. But tincal persisted in mineralogy, where it names a specific mineral species — monoclinic hydrated sodium tetraborate — distinct from its processed derivatives. F. W. Clarke's Data of Geochemistry (1908) still used tincal as the technical term for the naturally occurring form, and mineralogical references continue to do so today.