Jewelry Guide - Metals

Platinum

Although platinum was used in ancient Egypt and by the South American Incas, it was not as valued as gold. Until modern jewelers' tools were developed, platinum was more difficult to work with because it has an extremely high melting point. In the early 1900s, the best jewelry designers -- Cartier, Tiffany, Faberge -- began to create intricate and amazingly durable designs using platinum, and its popularity soared. It was the precious metal chosen for mounting some of the world's great diamonds, including the Hope Diamond, which is on display at the Smithsonian.

During World War II, the US government declared platinum a strategic metal, so white gold and silver were substituted for all white metal jewelry. After the war, platinum returned to the jewelry market and has had periods of great popularity. Platinum is very fashionable now; interest in the precious, coolly lustrous white metal has grown rapidly over the last five years.

Platinum is the heaviest of the precious metals. Platinum is a family group of six metals: platinum, palladium, rhodium, ruthenium, iridium, and osmium.

Like gold and silver, platinum is considered a "noble metal," which means that it will not oxidize or corrode. Unlike gold and silver, platinum in its pure state is extremely strong and durable and doesn't need to be alloyed. It will not wear down over the years or tarnish, as gold and silver can. When platinum is scratched, it does not lose material to the extent that other precious metals do.

Like the diamond, platinum is rare. 10 tons of ore are needed to produce every ounce of platinum, and processing the metal into jeweler's quality platinum takes five months. In the United States, all platinum jewelry is either 90% platinum and 10% iridium or 95% platinum and 5% ruthenium. It is always stamped "IRIDIPLAT," "900pt," or "pt 900" when it is 90% platinum and "PLAT," "950pt" or "pt950" when it is at least 95% platinum.

The two major sources of platinum in the world are South Africa and Russia. 90% of South Africa's platinum is reserved for industrial uses. Platinum is used in many essential modern goods. It is an important component of gasoline, fertilizers, fiber-optic cables, anti-cancer drugs, explosives, and pacemakers; all catalytic converters in automobiles depend on it.

Platinum is fifteen times more rare than gold, and fifty times more rare than silver. It is so rare, in fact, that all the platinum ever mined in the world would fit into the average-size living room.