Densest naturally occurring element
22.59/1 gram(s) per cubic centimetre
Not Applicable ()
Osmium (given the symbol Os and the atomic number 76) is the densest naturally occurring element. Its density is 22.59 g/cm3, which is just greater than iridium (22.56 g/cm3) and approximately double that of lead (11.34 g/cm3). Discovered in 1803 by Smithson Tennant and William Hyde Wollaston, in London, UK, the discovery was documented in a letter to the Royal Society on 21 June 1804. Because of the toxic nature of oxides of osmium, it is rarely used in natural form and is most commonly used as an alloy with other metals. Its hard wearing attributes make it ideal for use in alloys at the tips of fountain pen nibs as well as for electrical contacts.