The original discovery of ruthenium is thought to have occurred in 1828, when Swedish chemist Jons Jacob Berzelius and Russian chemist Gottfried W. Osann examined the residue after dissolving crude platinum ore in aqua regia (a concentrated solution of hydrochloric and nitric acids).

A small amount of ruthenium is used to harden platinum and palladium and can also be alloyed with these metals to form electrical contacts to improve wear resistance. Adding 0.1% ruthenium increases the corrosion resistance of titanium by a factor of one hundred. Ruthenium is a suspected carcinogen, and its compounds can seriously contaminate the skin. Ruthenium tetroxide (RuO 4 ) is highly toxic.

Ruthenium has catalytic properties; for example, hydrogen sulfide can be photo-decomposed in the presence of an aqueous suspension of cadmium sulfide particles loaded with ruthenium dioxide.

Interestingly, ruthenium is used in some Parker nibs, such as the Parker 51 nib marked "RU", which is composed of 96.2% ruthenium and 3.8% iridium.