The term “borax” is used to refer both to a mineral and to a
refined compound with numerous applications. The mineral takes the
form of colorless to white soft crystals, which can sometimes be
tinged with brown, yellow, or green. When struck against another
material, borax leaves a crumbly white streak. The substance is
also known as sodium tetraborate or disodium tetraborate, and it
has been known to humans for thousands of years. The mineral is a
chemical compound of the element boron, and the chemical formula
for borax is Na2B4O7**0H2O.
The word “borax” comes from a Persian word, burak, which was used
to refer to borax and other borate salts in the Middle East, picked
up by the Romans, and adopted by the Middle English. Borax and
related salts were used in the preservation of both food and
mummies, as well as to make pottery glazes in China and as a
cleaning material. In Medieval Europe, borax was used as a flux in
soldering, to scour metal before it was welded together. Borax is
still used for similar purposes today, although it is more heavily
refined for purity.
