A natural product composed of hydrated sodium borate. Borax is produced by the evaporation of water in shallow lakes. Borax was used by the Egyptians for mummification and by the Romans for glassmaking. In the 9th century, it was used as a flux for soldering gold in Arabia and by the 10th century, borax was being used in ceramic glazes in northern China. By the 13th century, tincal (borax) was regularly imported from Tibet to Europe for use in Venetian glass. The white powder is now mined from deposits in India, Russia, Persia, and the U.S. (California). Borax is used as a flux, cleansing agent, tanning agent, water softener, preservative, fungicide, and as an alkaline ingredient in glass, ceramics, and glazes.
Synonyms and Related Terms
sodium borate decahydrate; sodium diborate; tincal; tincalconite; tincar; hydrated sodium boration; sodium tetraborate; rasorite; Sporax®; bórax (Esp., Port.); borace (It.)
Soluble in water. Sweetish, alkaline taste.
Cleavage is perfect in one direction, good in another.
Translucent to opaque.
Fracture = conchoidal. Streak = white. Luster = vitreous to greasy.
|Mohs Hardness||2.0 - 2.5|
|Molecular Weight||mol. wt. = 381.4|
|Refractive Index||1.4630 (fused)|
Hazards and Safety
Toxic by ingestion. LD50 = 4500-6000 mg/kg. Skin contact can cause irritation.
Mineralogy Database: Borax
Sources Checked for Data in Record
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 108
- The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983
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- Wikipedia, the free encyclopedia, at http://www.wikipedia.com Comment: http://en.wikipedia.org/wiki/Borax (Accessed Sept. 2, 2005)
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- Encyclopedia Britannica, http://www.britannica.com Comment: borax" Encyclopædia Britannica [Accessed December 4, 2001