Platinum, a highly valued and desired metal, has a wide range of uses, including jewelry, catalytic converters, electrical contacts, pacemakers, medication and magnets. Because it is rare — there are only about 5 parts per billion by weight in Earth's crust, platinum tends to be very pricey, as anyone looking to buy a platinum wedding ring might discover.
Platinum is a silver-white metal — it was once known as "white gold." It is extremely resistant to tarnishing and corrosion (which makes it known as a "noble metal") and is very soft and malleable, making it easy to shape; ductile, making it easy to stretch into wire; and unreactive, which means it doesn't oxidize and is unaffected by common acids.
Platinum is one of the transition metals, a group that includes gold, silver, copper and titanium — and most of the elements in the middle of the periodic table. The atomic structure of these metals means they can bond easily with other elements.
It is also one of the densest elements at 12.4 ounces per cubic inch (21.45 grams per cubic centimeter), a little more than 21 times the density of water or 6 times the density of a diamond. These properties lead to many uses for this very rare and precious metal.