Platinum (Pt) is a very heavy precious metal, silver-white in color. It is the best known and most widely used of the six platinum group metals, which include iridium, osmium, palladium, rhodium and ruthenium. Platinum has a high melting point -3223°F / 1773°C- and a very high specific gravity of 21.46. One cubic foot of platinum weighs about 21 times as much as a cubic foot of water.
Platinum is a popular metal for use in the jewelry industry because of its many desirable properties. In its pure state platinum is soft, like pure gold. To add hardness, small amounts of iridium are added. The form of platinum generally used in the jewelry industry consists of an alloy of 95% pure platinum and 5% iridium (Pt 950). With its excellent properties of strength, tarnish-resistance and workability, platinum lends itself to the fabrication of delicately designed jewelry items and gem settings.
Do not confuse Platinum with white gold or Palladium jewellery. They may have similar appearance but the differences in market value are substantial. White gold is a gold (Au) alloy, whereas Palladium (Pd) and Platinum (Pt) are two unique elements. Make sure the Pt 950 or Pt 900 stamp is physically on the piece when purchasing Platinum jewelry as these are the only 2 acceptable stampes in the trade. Beware when you see stamps such as PLAT, Pt 750, Pd 950. Chances are they do not contain a minimum of 90% Platinum content.