photo credit: Denis Finnin,
© American Museum of Natural History

A large boulder of harzburgite, an igneous rock from the Stillwater complex with chromitite layers running through it. This platinum ore boulder comes from an area of the complex where platinum and other precious metals are concentrated. Most of the world's chromium is mined in South Africa. Chromium's chief use is in the steel industry and is the component of stainless steel that renders it 'stainless' — resistant to corrosion.