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 Platinum Jewelry Information
Platinum jewelry, like gold jewelry, has a long and distinguished history. Its use began in antiquity and it has undergone resurgence in popularity over the last 200 years. Platinum was held in high esteem during early Egyptian times. Native people in South and Central America worked it as early as 100 B.C. Spanish conquistadors discovered platinum artifacts among the gold they were seeking when they came to the new world. They named the curious metal "platina," or "little silver." They also considered it worthless, and discarded it. Platinum didn't reach Europe until the 18th century, but then it caught on in a big way. King Louis XVI elevated it by terming it "the metal of kings." For centuries, the only large amounts of platinum outside of South America were found in Russian mines. Russia used platinum coins in the 19th century. In Spain, some gold coins were faked by gold-plating platinum coins.
Nowadays, platinum is far more valuable than gold. Platinum's initial uses were probably limited by its hardness and its very high melting point. The early forging and casting techniques made it quite a difficult metal to work with. During the latter part of the 19th century, and the first half of the 20th, platinum was the premier metal for all-important jewelry. Platinum dominated the world of jewelry design during the Edwardian era, and the Art Deco period, well into the 1930s.
It all came to an abrupt end in World War II, when platinum was declared a strategic metal and its use banned for all non-military purposes. Platinum has many industrial applications, which made it invaluable to the military during the war. Platinum is vital to the automotive industry as well as to electrical engineering, electronics and petrochemicals. The medical and dental fields also use it to a great degree. Every car in the United States has platinum in its catalytic converter, which reduces emissions. Only about one-third of the platinum mined today is used in jewelry, where it consistently commands higher prices than the purest gold. Because of its many uses, almost all platinum mined and refined is immediately committed to use. An interesting note: There are no stockpiles or "reserves" of platinum in any government or banking storage.
The appeal of platinum is in its appearance. Its white luster is unique. It is also the strongest precious metal used in jewelry, and is almost twice as heavy as 14-karat gold. This weight is one of platinum's strongest selling points, because it gives "heft" to fine jewelry, which people naturally equate with value.
In recent years platinum has rapidly grown in popularity. It's become the new choice for many diamond engagement rings because its luster brings out the brilliance of diamonds far better than gold. Many fashion consultants agree that platinum (and white gold) is more compatible with fairer skin tones. The Japanese seem to be listening -- almost 85% of platinum jewelry produced every year is purchased by Japanese consumers!
Despite its growing popularity, platinum remains one of the world's rare metals. The annual worldwide production of platinum amounts to some 160 tons, compared to about 1,500 tons of gold. It can be found in just a handful of regions of the world. The mining and refining processes are both arduous and time-consuming. For example, in order to extract a single ounce of platinum, about 10 tons of ore need to be mined. After that, the refining process takes a full five months.
Platinum in jewelry is actually an alloyed group of six heavy metals, including platinum, palladium, rhodium, ruthenium, iridium and osmium. These other metals are so similar to platinum in weight and chemistry that most were not even distinguished from each other until early in the nineteenth century. Today, it is often alloyed with copper and titanium. It's the only precious metal used in fine jewelry that is 90% to 95% pure, largely hypoallergenic, and tarnish-resistant. Look for platinum wedding rings marked 900Pt, 950 Plat, or Plat. One final word about precious metals: Like gold, platinum is durable, sturdy and dependable, making it an ideal setting for your precious diamond jewelry. However, to get a lifetime of enjoyment from your jewelry, be sure to keep it clean and safe. Do not wear platinum jewelry during rough work or when handling harsh chemicals. Store it in a fabric-lined box away from other pieces so it does not get scratched. Finally, check any diamond settings periodically for possible damage to prongs or bezels. If you see a loose prong, or if the setting looks out of line, immediately bring it to a professional for repair.
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Material
Platinum is a chemical element in the periodic table that has the atomic symbol Pt and an atomic number of 78. A heavy, malleable, ductile, precious, grey-white transition metal, platinum is resistant to corrosion and occurs in some nickel and copper ores along with some native deposits. Platinum is used in jewelry, laboratory equipment, electrical contacts, dentistry, and automobile emissions control devices. Platinum bullion has the ISO currency code of XPT.
Notable Characteristics
When pure, the metal appears greyish-white and firm. The metal is corrosion-resistant. The catalytic properties of the six platinum family metals are outstanding. For this catalytic property, platinum is used in catalytic converters, incorporated in automobile exhaust systems, as well as tips of spark plugs.
Platinum's wear- and tarnish-resistance characteristics are well suited for making fine jewelry. Platinum is more precious than gold. The price of platinum changes along with its availability, but its price is normally slightly less than twice that of gold. In the 18th century, platinum's rarity made King Louis XV of France declare it the only metal fit for a king.
Platinum possesses high resistance to chemical attack, excellent high-temperature characteristics, and stable electrical properties. All these properties have been exploited for industrial applications. Platinum does not oxidize in air at any temperature, but can be corroded by cyanides, halogens, sulfur, and caustic alkalis. This metal is insoluble in hydrochloric and nitric acid, but does dissolve in the mixture known as aqua regia (forming chloroplatinic acid). Common oxidation states of platinum include +2, and +4. The +1 and +3 oxidation states are less common, and are often stabilized by metal bonding in bimetallic (or polymetallic) species.
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Applications
* As a catalyst in the catalytic converter, an optional (though often mandatory by law) component of the gasoline-fueled automobile exhaust system (see "Notable characteristics" in this article).
* As a catalyst in fuel cells. Reducing the amount of platinum required (and thus cost) is a major focus of fuel cell research.
* Certain platinum-containing compounds are capable of cross-linking DNA and kill cells by similar pathways to alkylating chemotherapeutic agents. Cisplatin, carboplatin and oxaliplatin are licensed examples of this class of drugs.
* Platinum resistance thermometers.
* Electrodes for use in electrolysis.
* In the Clark polarographic electrode for measuring oxygen tension.
* A wide range of jewelry
* As a catalyst in the curing of silicone elastomers.
* As a catalyst in glow plugs in some model engines.
* Crucibles for high temperature melting of glass (for example) up to 1500°C better if alloyed with rhodium (10-40% of Rh).
* In photography, it is sometimes used for archival printmaking. Platinum prints display a greater range of tones than other Black and White printing methods. Additionally platinum's chemical stability makes for extremely long-lasting prints. The disadvantage of this method, in addition to the high cost, is that platinum is less light sensitive and prints must be contact printed at the same size as the negative. Therefore, enlargements can only be made by making an enlarged negative.
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 History
Naturally-occurring platinum and platinum-rich alloys have been known for a long time. Though the metal was used by pre-Columbian Native Americans, the first European reference to platinum appears in 1557 in the writings of the Italian humanist Julius Caesar Scaliger (1484-1558) as a description of a mysterious metal found in Central American mines between Darién (Panama) and Mexico ("up until now impossible to melt by any of the Spanish arts"). The word platinum comes from the Spanish word platina, meaning "little silver."
Platinum was discussed by astronomer Antonio de Ulloa and Don Jorge Juan y Santacilia (1713-1773), both appointed by King Philip V to join a geographical expedition in Peru that lasted from 1735 to 1745. Among other things, Ulloa observed the platina del pinto, the unworkable metal found with gold in New Granada (Colombia). British privateers intercepted Ulloa's ship on the return voyage. Though he was well-treated in England, and even made a member of the Royal Society he was prevented from publishing a reference to the unknown metal until 1748. Before that could happen Charles Wood independently isolated the element in 1741. Major finds were discovered in Russia in 1819, which produced around 90% of the global Platinum production at the turn of the 20th century.
Due to its rarity, greater difficulty to work with and the need to alloy it with (at the time) an even more expensive metal iridium, platinum was only used in a limited way in jewelry at the end of the 19th century. This changed at beginning of the 20th century when most diamond ring mountings and most exclusive jewelry were almost completely made of Platinum.
The alchemical symbol for platinum was made by joining the symbols of silver and gold.
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Occurrence
Platinum is an extremely rare metal, occurring as only 5 ppb in the Earth's crust. In 2005, South Africa was the top producer of platinum with almost 80% world share followed by Russia, Canada and Botswana, reports the British Geological Survey.
Platinum is often found chemically uncombined as native platinum and alloyed with iridium as platiniridium. The platinum arsenide, sperrylite (PtAs2), is a major source of platinum associated with nickel ores in the Sudbury Basin deposit in Ontario, Canada. The rare sulfide mineral cooperite, (Pt,Pd,Ni)S, contains platinum along with palladium and nickel. Cooperite occurs in the Merensky Reef within the Bushveld complex, Gauteng, South Africa.
Platinum, often accompanied by small amounts of other platinum family metals, occurs in alluvial placer deposits in the Witwatersrand of South Africa, Colombia, Ontario, the Ural Mountains, and in certain western American states.
Platinum is produced commercially as a by-product of nickel ore processing in the Sudbury deposit. The huge quantities of nickel ore processed makes up for the fact that platinum is present as only 0.5 ppm in the ore.
Platinum exists in relatively higher abundances on the Moon and in asteroids - much terrestrial platinum is mined where asteroids have hit.
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Precautions
According to the Centers for Disease Control and Prevention, short-term exposure to platinum salts “may cause irritation of the eyes, nose, and throat” and long-term exposure “may cause both respiratory and skin allergies.” The current OSHA standard is 0.002 milligram per cubic meter of air averaged over an 8-hour work shift.
Certain platinum complexes are used in chemotherapy and show good anti-tumor activity for some tumors. Cisplatin is particularly effective against testicular cancer; cure rate was improved from 10% to 85%. However, the side effects are severe. Cisplatin causes cumulative, irreversible kidney damage and deafness.
As platinum is a catalyst in the manufacture of the silicone rubber and gel components of several types of medical implants (breast implants, joint replacement prosthetics, artificial lumbar discs, vascular access ports), the possibility that platinum free radicals could enter the body and cause adverse effects has merited study. The FDA and other countries have reviewed the issue and found no evidence to suggest toxicity in vivo.
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Rarity and Color
Platinum's rarity as a metal has caused advertisers to associate it with exclusivity and wealth. "Platinum" credit cards have greater privileges than do "gold" ones. "Platinum awards" are the second highest possible, ranking above gold, silver and bronze, but below "Diamond". For example, a musical album that has sold more than 1,000,000 copies will be credited as "platinum." And some products, such as blenders and vehicles, with a silvery-white color are identified as "platinum". Platinum is considered a precious metal, although its use is not as common as the use of gold or silver. The frame of the Crown of Queen Elizabeth the Queen Mother, manufactured for her Coronation as Consort of King George VI, is made of platinum. It was the first British crown to be made of that metal.
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Production
In order to obtain pure platinum, the ore is crushed, made into a slurry, and then mixed with a detergent containing 'collector' molecules. Air is then blown through the mixture, enabling the grains of metal minerals to be separated from the rest of the mixture. World supply of platinum is around 7 million troy ounces (199,000 kg) per year. Platinum's prices fluctuate around USD $1250 per troy ounce ($40/g).
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