Platinum is a pure elemental metal, which, like other elements, doesn't break down into further components. It is element number 78 on the periodic table and has an atomic mass of 195.08. Platinum is relatively unreactive and is found naturally mixed with small amounts of other metals in its family group.
While the discovery of platinum is traceable to the 1730s or 1740s, no one is sure who made the discovery, according to About.com. Pre-Cambrian Indian artifacts show its use in a relatively pure form. Reference.com says the Spanish make reference to the metal in mining for silver in Central America in the 1550s, but they considered it an impurity, so it was discarded.
While halogens, sulfur and caustic alkalis attack platinum, it doesn't react with oxygen even when heated to a high temperature. It does absorb large quantities of hydrogen, which it releases as red heat.
Platinum is a silver-white metal that resists wear and tarnish, making it a good choice for use in making fine jewelry. In the medical field, it is used in laboratory utensils and surgical tools as well as surgical implants, such as replacement valves and pacemakers. Dentists use platinum extensively. The electronics industry uses it to make contact points and electrical resistance wires.