<P> The United States has traditionally been the major world supplier of this metal, supplying 45% of world production even as recently as 1995 . Today, the US market share is at 7%, with a single domestic producer left, US Magnesium, a Renco Group company in Utah born from now - defunct Magcorp . </P> <P> The name magnesium originates from the Greek word for a district in Thessaly called Magnesia . It is related to magnetite and manganese, which also originated from this area, and required differentiation as separate substances . See manganese for this history . </P> <P> In 1618, a farmer at Epsom in England attempted to give his cows water from a well there . The cows refused to drink because of the water's bitter taste, but the farmer noticed that the water seemed to heal scratches and rashes . The substance became known as Epsom salts and its fame spread . It was eventually recognized as hydrated magnesium sulfate, MgSO 4 7 H 2O . </P> <P> The metal itself was first isolated by Sir Humphry Davy in England in 1808 . He used electrolysis on a mixture of magnesia and mercuric oxide . Antoine Bussy prepared it in coherent form in 1831 . Davy's first suggestion for a name was magnium, but the name magnesium is now used . </P>

Similar chemical properties of mg and ca are due to