Melinda Maria Harron, age 11, of San Francisco, CA: for her question:

Where do we get magnesium?

Magnesium is a silvery white metal, less than twice as heavy as water. It is a very plentiful metal. Only aluminum and iron are more abundant. But until recently, we have not used much magnesium. It occurs in a few ores, but the worlds great reservoir of magnesium is in the sea. A cubic mile of sea water contains about six million tons of dissolved magnesium.

Most of our magnesium is processed at Freemont, Texas. A chemical plant extracts the silvery metal from sea water from the Gulf of Mexico. Magnesium is also mined from ores in California, Nevada and Washington.