Platinum is a rare metal valued for its use in making jewelry and watches and is almost twice as expensive as gold. It has a highly pleasant appearance and is resistant to tarnishing. Other uses of this metal include its use as a catalyst in many chemical processes, the manufacture of laboratory apparatus that require high temperature applications and for making electrical contacts for switches and other devices.
Platinum is a soft silvery-white metal that can easily be drawn into wire or hammered into various shapes. Because it is so soft it cannot be used for jewelry in its purest state. Therefore iridium or another metal of the platinum group has to be added to it to make it hard. Platinum is one of the heaviest metals with a density of 21.45g per cubic cm at 20ºC. It does not oxidize in air and is not affected by acids, but it does dissolve in hot aqua liquids.
Just about all occurrences of platinum are found in alkaline rocks, especially those rich in the mineral olivine. It is also found in stream beds and in sand that has formed as a result of rock erosion. Large deposits of platinum are found in Alaska, Columbia and Russia. There are also large amounts that result from mining copper and nickel, especially in Canada and South Africa.
Chloroplatinic acid is one of the most important compounds of platinum. This is formed by dissolving the metal in aqua regia and is used for electroplating and other purposes.