Ruthenium is a rare metal with a silver-gray lustre and is a member of the platinum group metals, which are found along with other platinum group metals in minerals such as pyrite and pyrotoxin. The six platinum group metals are ruthenium, rhodium, palladium, palladium, iridium, and platinum, which are grouped in rectangles in the periodic table and have similar properties.

Ruthenium, the rarest of the platinum group metals, is mainly mined along with nickel or platinum, and only about 12 tons are mined per year. The pure metal ruthenium has few uses, but it is widely used as alloys with other metals.
The addition of ruthenium to platinum and palladium can increase the hardness of the metal to make electrical contact alloys and cemented carbides, and is often used in jewelry. Alloys or compounds of ruthenium and other metals such as rhodium, iridium, bismuth, etc., can also be used to make resistors, solar cells, electrical contacts, or in catalysts, among others. One of the famous Parker 51 fountain pen uses ruthenium-iridium alloy on the gold nib.