What is Osmium used for?
Osmium is a hard and brittle transition metal. It has the highest density of any known element at 22.59 g/cm^3.
Pure osmium is volatile and very toxic. As a pure metal it does not have any applications.
Instead it is used as an alloy with metals that lie in the platinum group of metals. The presence of osmium makes the alloys very durable and hard. This makes them ideal for applications that require the material used to be one that will not wear down as it is repeatedly used. Some applications of osmium alloys are in the nibs of fountain pens, electrical contacts and surgical implants. Osmium also finds use in fingerprint detection and in staining fatty acids when they are being viewed using high magnification microscopes.