, deriving from the Macedonian
tribe name Magnetes
, was the name of two cities in ancient Lydia
) founded by the Greekss
. One of them, Magnesia ad Sipylum is famous as the site of the Battle of Magnesia
. Its ruins lie close to present day Manisa.
In geology, magnesia is a natural form of magnesium oxide, also called periclase. Stones from the Magnesia region contained both magnesium oxide and hydrated magnesium carbonate as well as iron oxides (such as magnetite). Thus these stones, called Stones from Magnesia in antiquity, with their unusual magnetic properties were the reason the term magnetism was coined.
In alchemy and early chemistry, magnesia alba was the name for an indefinite hydrated mixture of magnesium hydroxide and magnesium carbonate.
See also milk of magnesia.