American Gem Society
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Platinum Jewelry Palo Alto


 

Platinum is a metal of great purity and beauty. Its strength and durability make it a superior metal for setting fine gemstones, and its whiteness of color enhance the beauty of a fine diamond like no other metal. Platinum is rare; only 120 to 130 tons of platinum are mined each year, 1/20th of the amount of gold mined. To obtain one ounce of platinum, roughly ten tons of ore must be mined, as opposed to three tons of ore for one ounce of gold. Platinum has been used since ancient Egyptian times, yet all the platinum ever mined would fit into a cube not much more than 20' on each side.

Platinum In History

Like gold, platinum dates from the ancients. Its first reported use was by the Egyptians about 3,000 years ago, and it was used throughout Central and South America by the Incas as early as 200 B.C. (the Conquistadors reported deposits of platinum in the New World in the 1500's). Today, South Africa accounts for roughly half of the world's annual platinum production. But deposits are rare, and found in only a few locations around the world.

The use of platinum in jewelry by the Europeans was first reported at the court of Louis XVI of France, around the year 1780. Widespread use of platinum jewelry dates from the late 19th and early 20th Centuries. Many of the famous 19th-century jewelers, such as Carl Faberge and Louis Cartier prized platinum for its luster and durability. It was particularly popular in jewelry of the Edwardian Period (1901-1914). From this period, platinum became the metal of choice for the finest jewelry up until World War II, when it was requisitioned for military use, and replaced by new alloys of white gold. The 1990's have fueled a new demand for platinum in jewelry and it is once more the metal of choice for the finest jewelry.

Higher Purity Alloys

Platinum is one of six metals belonging to a group known as the 'platinum group.' The other metals in this group are iridium, ruthenium, palladium, rhodium, and osmium. Platinum, like gold, is a 'noble' metal, which means that it does not oxidize, or corrode, when it comes into contact with the atmosphere. It is hypoallergenic and resists tarnish. Platinum is very rare, requiring as much as ten tons of ore to produce a single ounce. Gold, by contrast, requires 3 tons of ore to produce a single ounce.

Due to the hardness and durability of platinum, it requires the addition of only minor amounts of other metals for use in jewelry. This means it is an alloy of very high purity. The most widely used platinum alloys are either 90% platinum with 10% iridium (shown '10% irid. plat.', or '900 plat.'), or 95% platinum with either 5% ruthenium or 5% iridium (shown '950 Plat', '950 Pt.', or simply 'Plat.'). If a piece is marked 'Platinum' , 'Plat.', or 'Pt.', it must contain at least 95% pure platinum. Note that both four-letter and two-letter abbreviations for platinum are commonly used.

Other alloys found in the United States are '850 Plat.' (85% pure) and '600 Plat.' (60% pure). Jewelry containing at least 50% pure platinum and at least 95% platinum group metals (i.e. platinum, palladium, iridium, osmium, rhodium, and ruthenium) is marked with the platinum content followed by the content of the other metal (e.g. '600 Plat. 350 Irid.'). Jewelry containing less than 50% pure platinum content cannot be marked with the word 'platinum' or any abbreviation thereof. Federal laws regulate the accuracy of all jewelry metal alloys and, like karat gold jewelry, platinum jewelry must be stamped with the quality of the alloy and the manufacturer's trademark.

Platinum and White Gold

Contrary to appearances, platinum and white gold are very different metals. Platinum, as explained above, is a separate and distinct metal. White gold is simply yellow gold mixed with an alloy to make it appear white. The alloy usually consists primarily of copper, zinc, and either nickel, platinum, or palladium. White gold alloys, especially 18 karat alloys, usually appear slightly yellowish. Consequently, most white gold jewelry is electroplated with rhodium, a platinum group metal, to make it appear more white.

Platinum Art Deco Brooch

Art Deco Brooch

 






Platinum Diamond Ring

Edwardian Ring