Osmium is named from the Greek osme, a smell and was discovered in 1803. Osmium occurs in iridosmine and in platinum bearing river sands of the Urals, North America and South America. The metal is lustrous, bluish-white and is extremely hard and brittle. It has the highest melting point and lowest vapor point of the platinum metals. The metal is used almost entirely to produce very hard alloys, with other metals of the platinum group, for fountain pens, instrument pivots, phonograph needles and electrical contacts. The tetroxide has been used to detect fingerprints and to stain fatty tissue for microscope slides.