Platinum is one of the three precious metals. The other two being gold and silver. Of the three Platinum is the rarest of all and, subsequently, the most expensive currently running at about twice the value of gold.

Platinum is harder than gold or silver and has a higher melting point which means it is more difficult to alloy or join with the other two metals. However, it does not tarnish or corrode and is hypoallergenic so almost never causes allergic reactions

This makes it ideal for gemstone setting and platinum is used extensively for the more expensive setting for diamonds and other gems. Jewelry platinum is often an alloy of 90- percent platinum and 10 percent iridium which is much harder. This gives the platinum jewelry more hardness and therefore more durability.

The atomic number for Platinum is 78, the atomic weight 195.078. It was known to be used by pre-Columbian South American Indians, and later rediscovered in the 18th century. Its first use for coins was by Russia in 1828, following the discovery of large platinum deposits in the Ural mountains in 1822. The only United States issues struck in platinum are the pattern half dollars of 1814 and modern platinum Eagles.

It is also used in Watches bracelets and other fine jewelry as well as laboratory equipment, electrical contacts, dentistry, and automobile emissions control devices.

This entry was posted on Tuesday, September 26th, 2006 at 9:35 am.