When it comes to finding that perfect piece of jewelry, many of us are concerned with the dazzling gem (or gems, depending on the size of your wallet). Much of the time, settings, bands and chains end up playing second fiddle to the sparkling jewels they hold.
However, there's a reason your neighbor hides his gold coins, and your dad locks the family silverware in a safe. Gold and silver are two extremely valuable metals -- deemed as precious because of their rarity, socioeconomic importance, non-reactivity and ability to withstand corrosive and oxidative forces [source: Swanson]. From year to year, even month to month, prices of these valuable metals fluctuate greatly.
Besides looking great around someone's neck or finger, these valuable metals also have industrial purposes. For example, platinum-group metals are used to create lab equipment, dental materials and electronics [source: Loferski]. Precious, or valuable, metals also serve as a means of investment as these commodity prices have continued to rise over the years. It's important to note that the common unit of weight for precious metals is the troy ounce -- equivalent to 1.1 standard ounces or .031 kilograms [source: BullionVault].
Let's take a look at the most valuable metals around and what makes them so special. Up first: a metal that cries when it gets bent out of shape.
Gold bars at the U.S. Bullion Depository, Ft. Knox, Ky. in 1974.
Image Credit: AP Photo/Barry Thumma
10. Indium
If valuable metals could have personalities, then indium would be the cry-baby among the bunch. It's a big softy (figuratively and literally), blue inside (was named for its indigo spectral line) and lets out a high-pitched "cry" when bent [sources: Los Alamos, Encyclopedia Brittanica].
Indium is a rare metal produced from zinc-ore processing, as well as lead, iron and copper ores. In its purest form, indium is a white metal that's extremely shiny and malleable. It was used first widely during World War II, as a coating for bearings in aircraft engines. Indium can also be used to create corrosive-resistant mirrors, semiconductors, alloys and electrical conductivity in flat-panel devices [source: Tolcin].
In 2009, the average price for indium was $500 per kilogram ($15 per troy ounce), and the largest producers included China, South Korea and Japan [source: Tolcin]. Indium recycling or reclamation has become more popular as the price of indium rises.
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9. Silver
If every cloud really did have a silver lining, we'd all be enjoying lucrative rainstorms. That's because silver is one of the most valued metals on Earth. This lustrous white element, in its purest form, has the best electrical and thermal conductivity, as well as the lowest contact resistance of all the metals [source: Los Alamos].
You may know silver's common uses -- jewelry, coinage, photography, circuitry, dentistry, batteries -- but what about the surprising ones? Silver can be used to stop the spread of bacteria in cell phone covers, control odor in shoes and clothing and prevent mold in treated wood. In fact, some clouds may very well have real silver linings since silver iodide is used in cloud seeding [sources: Brooks, Los Alamos].
Silver can be found in such ores as horn silver and agentite. And silver is a valuable by-product of processing and smelting copper, gold and lead-zinc ores. In 2009, Peru, China, Mexico and Chile were the top producers of silver. The average price for silver that same year was $13.40 per troy ounce ($432 per kilogram), though prices rose in 2010 [source: Brooks]. Because of its many uses, silver is one of the most valuable metals exchanged today.
Three trucks of shiny new silver coins at the U.S. Mint in Denver in 1934.
Image Credit: AP Photo
8. Rhenium
Though perhaps not as well known as fellow precious metals like gold and platinum, silvery rhenium is one of the densest metals and has the third highest melting point [source: Los Alamos].
Because of its ability to withstand blistering conditions, rhenium, discovered in 1925, is used in high-temperature turbine engines. This cool-as-a-cucumber metal is also added to nickel-based superalloys to improve temperature strength [source: Polyak]. Other uses include filaments, electrical contact material and thermocouples.
Rhenium is a by-product of molybdenum, which essentially is a by-product of copper mining. Chile, Kazakhstan and the United States led world production of this valuable metal in 2009. Prices dropped dramatically that year for rhenium metal powder at $75 per troy ounce ($2,419 per kilogram). However, in June 2010, prices rose to about $141 per troy ounce ($4,548 per kilogram) [sources: Polyak, Roskill].
Find out which valuable metal was named in honor of the Greek goddess of wisdom on the next page.
7. Palladium
In 1803, William Hyde Wollaston discovered a way to separate palladium from its surrounding platinum ore. This grayish-white, precious metal is valued because of its rarity, malleability, stability under hot conditions and ability to absorb a considerable amount of hydrogen at room temperature [source: International Platinum Group Metals Association].
Palladium, named for the Greek goddess Pallas, is a member of the precious-metals group. Its valuable properties put palladium in high demand within various industries: Automobile makers rely on it for their catalytic converters to reduce emissions; jewelers use palladium to create "white gold" alloys; and electronics manufacturers have the option of plating with it, as palladium has excellent conductive traits. [sources: IPGMA, Loferski].
Though prices have jumped over the last few months, the cumulative average price for 2009 was $263 per troy ounce ($8,483 per kilogram) [source: Kitco]. Almost half of the world's palladium came from Russia in 2009, followed by South Africa, the United States, Canada and other various countries [source: Loferski].
6. Osmium
One of the densest elements on Earth, osmium is a bluish-silver metal discovered by Smithson Tennant in 1803. He also discovered iridium (our valuable metal no. 5) that year as well [source: Lloyd and Mitchinson]. There's debate about whether osmium or iridium is the heavier element.
Rare osmium usually is alloyed with the other platinum-group metals in nickel-heavy ores, and iridosuleis mined in parts of Russia and North and South America [source: Los Alamos]. In October 2010, the trading price of osmium was around $380 per troy ounce ($12,700 per kilogram) [source: Chard].
This very hard, brittle metal has an extremely high melting point which can be problematic when trying to manipulate it. For the most part, osmium is used to harden platinum alloys for electrical contacts, filaments and other uses. There are dangers associated with handling osmium, as it emits a toxic oxide that can cause skin and eye damage as well as lung congestion.
Find out what other precious metal knows how to keep its cool under sweltering conditions.
5. Iridium
If valuable metals could have mottos, iridium's would be "go big or go home." It is definitely the most extreme member of the platinum group. This whitish metal has an amazingly high melting point, is one of the densest elements around and stands as the most corrosion-resistant metal [sources: IPGA, Lenntech]. Water, air, even acid, have no real affect on iridium.
Because of its extreme properties, iridium is difficult to obtain and manipulate. It mostly comes from South Africa, is processed from platinum ore and as a by-product of nickel mining [source: IPGA]. In 2009, the average price of iridium was $420 per troy ounce ($13,548 per kilogram) [source: Loferski]. Its unique traits allow this hard metal (much harder than platinum) to contribute to advancements in medicine, electronics and automobiles, as well as in such products as pens, watches and compasses.
Even jewelers are trying to use iridium in a few exclusive pieces. With a high shine factor and a low-tarnish guarantee, iridium could make an amazing medium for those willing to front the cash.
4. Ruthenium
Russian scientist Karl Karlovich Klaus discovered ruthenium, a bright gray metal, in 1844. This member of the platinum metals retains many of the group's characteristics, including hardness, rarity and an ability to withstand outside elements -- to a point. It doesn't degrade at room temperature, but going above 800 degrees Celsius (1,472 degrees Fahrenheit) will eventually impact the metal [sources: IPGA, Encyclopedia Britannica].
Ruthenium is found among the same ores of its fellow platinum-group metals throughout areas of Russia and the Americas, including nickel-dense areas of Canada. In 2009, the average price of ruthenium was $420 per troy ounce ($13,548 per kilogram) [source: Loferski].
After a complex chemical process, the metal can be isolated and used for various purposes. Ruthenium can be added as an alloy to platinum and palladium in order to increase hardness (for jewelry) and better resistance (against corrosive agents, especially with titanium). Ruthenium has become quite popular in the electronics field, as a way to effectively plate electric contacts.
Get a literal gold mine of information on the next page.
3. Gold
Whether we're wearing it, paying with it, praying to it, starting wars over it or even being buried inside it, gold has always been a cherished commodity. Gold has enticed everyone -- from the ancient Egyptians who forged gold coffins to the 19th century prospectors who scoured California coast for nuggets.
Because of its desirability, durability and malleability, gold remains one of the most popular metals and investment options. For 2009, the average price for gold was $950 per ounce ($30,645 per kilogram); however prices for 2010 jumped even higher ($1,249 per ounce; $40,290 per kilogram) [source: George].
The largest miners of gold include South Africa, the United States, Australia and China. Gold is usually separated from surrounding rocks and minerals by mining and panning, upon which the metal is extracted with a combination of chemical reactions and smelting. Learn more about the process in How Gold Works.
Besides looking great on your fingers, neck and ears, gold has valuable industrial uses as well. Its conductivity makes it a great component of electronics, and its reflective surface helps create better radiation shields and office windows.
All of you bleached blondes will love this next valuable metal.
Times change, but gold's appeal is eternal, as demonstrated by this pre-Columbian mask from Peru.
Image Credit: AP Photo/Carlos Lezama
2. Platinum
The most affordable way for some of us to wear "platinum" is to dye our hair bright white and look like we walked out of an '80s music video. That's because real platinum, a dazzling, silvery metal, can drain a bank account fast. The average price in 2009 for one troy ounce of platinum was $1,187 ($38,290 per kilogram) [source: Loferski].
Found in South Africa, Russia, Canada and other countries, platinum has made a name for itself through its malleability, density and non-corrosive properties [source: Loferski, Los Alamos]. In addition, platinum is similar to palladium in its ability to withstand great quantities of hydrogen.
This valuable metal has become well known in the jewelry world for its lustrous look and remarkable resistance. Platinum is also used in fields like dentistry, weaponry and aeronautics.
1. Rhodium
Though its name may sound like a place where cowboys strut their stuff, rhodium is actually one of the world's most valuable metals. This shiny, silvery-colored metal is commonly used for its reflective properties -- in objects like search lights, mirrors and jewelry finish [source: Kitco].
Besides its popular metallic uses, rhodium is valuable for its catalytic applications within the automotive industry. Its high melting point and ability to withstand corrosion allow rhodium to be a crucial addition in many industrial fields.
This extremely rare and valuable metal is found in only a few places. In 2009, 60 percent of rhodium came from South Africa, followed by Russia. Though the price has been falling over the years, rhodium is still one of the most expensive metals around. According to Kitco, a world retailer of precious metals, the average monthly price of rhodium was $1,442 per troy ounce ($46,516 per kilogram) for 2009.
Paul McCartney may have sung about a man with a silver hammer, but to celebrate his pre-eminent status as a recording artist, the Guinness Book of World Records presented him with a rhodium disc [source: Kitco].
Learn more about valuable metals on the next page.
Datko, Karen. "How to Sell Your Old Gold Jewelry." MSN Money. March 26, 2008. (accessed Sept. 14, 2010). http://articles.moneycentral.msn.com/SmartSpending/ConsumerActionGuide/HowToSellYourOldGoldJewelry.aspx
DeYoung, John H. Jr. Director. National Minerals Information Center. U.S. Geological Survey. Personal correspondence. (Sept. 8, 2010).
Fenton, Michael. "Iron and Steel." Mineral Commodity Summaries 2010. U.S. Geological Survey. January 2010. (accessed Sept. 14, 2010). http://minerals.usgs.gov/minerals/pubs/mcs/2010/mcs2010.pdf
George, Michael. "Gold." Mineral Commodity Summaries 2010. U.S. Geological Survey. January 2010. (accessed Sept. 12, 2010). http://minerals.usgs.gov/minerals/pubs/mcs/2010/mcs2010.pdf
Lloyd, John and John Mitchinson. "The Book of General Ignorance." Random House, Inc. 2007. (accessed Sept. 12, 2010). http://books.google.com/books?id=1Mjd2GCRPmAC&q=osmium#v=snippet&q=osmium&f=false
Loferski, Patricia. "Platinum-Group Metals." Mineral Commodity Summaries 2010. U.S. Geological Survey. January 2010. (accessed Sept. 10, 2010). http://minerals.usgs.gov/minerals/pubs/mcs/2010/mcs2010.pdf
Los Alamos National Laboratory Chemistry Division. "Gold." Periodic Table of the Elements. Dec. 15, 2003. (accessed Sept. 11, 2010). http://periodic.lanl.gov/elements/79.html
Los Alamos National Laboratory Chemistry Division. "Indium." Periodic Table of the Elements. Dec. 15, 2003. (accessed Sept. 13, 2010). http://periodic.lanl.gov/elements/49.html
Los Alamos National Laboratory Chemistry Division. "Osmium." Periodic Table of the Elements. Dec. 15, 2003. (accessed Sept. 11, 2010). http://periodic.lanl.gov/elements/76.html
Los Alamos National Laboratory Chemistry Division. "Platinum." Periodic Table of the Elements. Dec. 15, 2003. (accessed Sept. 11, 2010). http://periodic.lanl.gov/elements/78.html
Los Alamos National Laboratory Chemistry Division. "Ruthenium." Periodic Table of the Elements. Dec. 15, 2003. (accessed Sept. 11, 2010). http://periodic.lanl.gov/elements/44.html
Los Alamos National Laboratory Chemistry Division. "Rhenium." Periodic Table of the Elements. Dec. 15, 2003. (accessed Sept. 11, 2010). http://periodic.lanl.gov/elements/75.html
Los Alamos National Laboratory Chemistry Division. "Silver." Periodic Table of the Elements. Dec. 15, 2003. (accessed Sept. 12, 2010). http://periodic.lanl.gov/elements/47.html
Polyak, Desiree. "Rhenium." Mineral Commodity Summaries 2010. U.S. Geological Survey. January 2010. (accessed Sept. 12, 2010). http://minerals.usgs.gov/minerals/pubs/mcs/2010/mcs2010.pdf
Roskill. "Rhenium: Market Outlook to 2015." 8th edition, 2010. (accessed Sept. 12, 2010). http://www.roskill.com/reports/minor-and-light-metals/rhenium/?searchterm=rhenium
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