Gold  |   Platinum  |   Silver  |   Diamonds  |   Emeralds  |   Rubies  |   Sapphires  |   Pearls

GOLD

Gold, a soft and highly-malleable metal, does not tarnish easily and comes in a variety of colors. Gold costs more than most precious metals and its softness can result in scratching and denting.

• Yellow gold jewelry: Yellow gold jewelry is non-corrosive and sturdy. Diamonds set in yellow gold benefit from color contrast, and slightly tinted stones can appear brighter.
• White gold jewelry: White gold jewelry has a shiny silver hue that makes it look like platinum. White gold is virtually non-tarnishing.
• Rose gold jewelry: Rose gold jewelry includes alloys that bring out deeper pink accents.

Gold's purity is measured in karats. Pure 24K gold is too soft to securely hold a stone so gold is alloyed with other metals such as silver, copper, and zinc to make it sturdier. Gold jewelry should be stamped with the karat mark ("K") along with the manufacturer's trademark and country of origin (if outside the U.S.). European karat markings are different than those in the U.S.

Spot gold-coated jewelry

Not all gold jewelry is gold to the core and in the United States metal less than 10K cannot legally be sold as gold. Most eBay sellers will make sure you know the exact gold content by weight of any piece they sell.

• Gold-filled jewelry: Gold-filled jewelry, also called gold overlay, has a layer of at least 10-karat gold bonded to the surface of a support metal. The karat gold must be at least 10 percent of the total weight.
• Gold plated jewelry: Similar to overlay, the gold content in gold-plated jewelry may be as little as 5-percent of the total weight.
• Jewelry with gold leaf: With gold leaf jewelry, a very thin layer of gold is applied by hand to the surface of an item.

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PLATINUM

Platinum jewelry is hypoallergenic, strong, durable, and tarnish resistant. Platinum costs more than gold and weighs more. Five heavy metals with similar chemistry and weight (iridium, osmium, palladium, rhodium, and ruthenium) naturally alloy platinum. Unlike gold, platinum jewelry contains platinum in nearly pure form. It should bear a stamp with a symbol to reveal purity:

• 900 Plat: The "900 Plat" stamp indicates that platinum is 90-percent pure platinum.
• 950 Plat/ Plat: A "950 Plat" or "Plat" stamp indicates that platinum is 95-percent pure platinum.

Platinum provides a sturdy grip for diamonds and gemstones, but the strength of the metal makes resizing platinum rings difficult.

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SILVER

Silver, a malleable and plentiful metal, costs less than other precious metals, but tarnishes easily and requires frequent care and cleaning. Too soft for use in jewelry in its pure form, most silver jewelry is sterling silver (92.5-percent silver and 7.5-percent copper). Sterling silver should be marked "sterling," "925," or "ster."

Most jewelers can easily resize a non-gemstone silver ring, plus or minus two sizes. However, resizing a silver ring with a gemstone can be difficult due to silver's properties when heated.

Maintain Your Gold, Platinum, & Silver Jewelry

You can help make your precious metal jewelry last longer by following a few simple steps. The jewelry you wear every day will experience the most wear and tear. Use common sense to help protect your precious metals.

• Be gentle on your jewelry: Avoid wearing scratch-prone precious metal jewelry during rough manual work or activities.
• Stay away from chemicals: Do not let precious metals come in contact with harsh chemicals or abrasive surfaces.
• Properly store silver jewelry: Store silver in a cool, dry dark place. To slow tarnishing, do not store directly on wood or plastic.
• Regularly clean your precious metals: Clean gold and platinum with soap, water, and a cloth or soft brush, if needed. Wash silver with soap and water. Be sure to dry it thoroughly with a soft cloth. Clean tarnished silver with a commercial polish, paste, or tarnish-removing wipe. Silver polish may remove intentional oxidation (shading of the metal), requiring professional re-oxidation.
• Take your jewelry to the pros: Inspect jewelry regularly for damage or loosening, and have it professionally repaired if the need arises. Even if you do not detect damage or loosening, have a professional jeweler inspect metal jewelry to make sure prongs and bezels remain intact.

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DIAMONDS

Know Diamond Cuts and Shapes

Diamond shapes range from oval, marquise, fancy, round, princess, emerald, peart, etc.

• Diamond cut grade: A standard grading report describes cut by the shape or outline of the diamond and the pattern of the facet arrangement (also known as cutting style).
• Diamond cut depth: Diamonds cut too shallow or too deep lose light through the bottom or sides, causing the stones to sparkle less.
• Diamond polish: A poor polish, or rough facets, can diminish a diamond's brilliance, as well as its value.

Determine Diamond Carat Weight

Diamond size is measured by weight in carats or points. Because larger diamonds are rare, prices rise considerably as carat weights increase. If your primary shopping concern is high carat weight, a moderate downgrade in carat size (e.g. 0.05) can save you a lot of money and still look beautiful.
1 Carat = 100 Points = 200 milligrams

Study Diamond Clarity

Most diamonds contain inclusions (tiny mineral traces or flaws) often invisible to the naked eye. A diamond's clarity is determined by the amount and severity of these inclusions. Flawless diamonds are very rare and more expensive. eBay sellers often describe the clarity of larger, solitaire diamonds by referring to the industry letter grading scale. For example, the International Gemological Institute (IGI) uses the following grading scale for clarity:

Consider Diamond Color

Most diamonds appear white to the naked eye, but they all include trace amounts of yellow color, with the most valuable diamonds falling in the colorless range. However, a deeply colored diamond such as a brilliant canary yellow diamond can cost more than its colorless counterpart.

Fancy diamonds, also called Z+ diamonds, come in a variety of colors including deep yellow, pink, green, orange, blue, red, and black.

Spot Certified Diamonds

Many sellers include diamond appraisal (estimated retail value) and certification information in listings. Certificates, official documents issued by third-party gemological labs, include specifics about an individual gem (at least the four Cs) independent of market value. It can include information about diamond quality, validation that a diamond is organic, and the serial number on the girdle of laser-inscribed diamonds.

• Look for reputable gemological labs: Make sure a reputable gemologist or gemological lab issued the grading certificate. You'll have trouble determining impartiality and stringency of no-name laboratories.
• Evaluate the grading certificate's photo: Look for listings with a picture of the grading certificate and its serial number. Some labs offer online services where you can type in the serial number and verify that the lab graded the diamond and that the specifications are the same.
• Discover the origin of a diamond: Ask sellers for more information about their process for confirming the origin of their diamonds so you don't end up buying a conflict diamond. Some eBay sellers specify their diamond "Kimberly Process confirmed." The Kimberly Process, formally launched in January 2003, attempts to certify international diamonds and identify the origins of each diamond.

Research gemological labs

Acquaint yourself with gemological labs before purchasing your diamond. Lab reputations may very and change over time. Popular labs that certify diamonds and gemstones include:

• Gemological Institute of America (GIA): Many in the industry consider GIA the gold standard of diamond graders. Established in 1931, the not-for-profit GIA has its headquarters in Carlsbad, California and has a presence in a number of locations worldwide.
• International Gemological Institute (IGI): IGI grades diamonds and gemstones from its headquarters in New York and several other U.S. locations.
• American Gem Society Laboratories (AGSL): Founded in 1978, the AGSL is based in Las Vegas, Nevada.
• European Gemological Laboratory USA (EGL-US): There are a few independently owned grading labs that carry the EGL name. EGL-US certificates, however, are the only EGL certificates permitted in the United States. EGL-US has been independently owned since 1986, and is based in New York.

Select Other Diamonds & Crystals

Not all diamonds come straight out of nature. Common enhancements include:

• Clarity-enhanced diamonds: Clarity-enhanced diamonds have undergone treatment to remove visible imperfections. In the clarity enhancement process microscopic amounts of material similar to a diamond are inserted into the flaws. Light then flows freely through the diamond eliminating the imperfection from view. Because the material is used in small quantities, it does not add to the weight of the diamond.
• Color-enhanced diamonds: Color-enhanced diamonds have undergone treatment to alter or heighten color. A number of procedures can change a diamond's natural color, including irradiation using high-energy particles. Depending on resulting color, "after" colored diamonds can be more expensive than their untreated counterparts. The safe irradiation process does not affect any aspect of the diamond other than color.
• Laser-drilled diamonds: Laser-drilled diamonds have undergone treatment to remove inclusions with a laser. Laser drilling provides permanent inclusion removal and does not affect the diamond's strength.

Maintain Your Diamonds

Diamonds are the hardest naturally-occurring substance on Earth, but they still can chip. When you shop for diamond jewelry, choose your setting wisely. Four-prong, six-prong, and low-profile channel or bezel settings are more apt to protect your diamonds. When you get your diamond jewelry home, store pieces individually in soft cloth pouches to prevent jewels from bumping against one another.

Clean your diamonds

Dust, skin oil, and other unclean substances can cause your diamonds to lose their sparkle. Clean your diamonds from time to time in soap and water. Air dry and polish with a soft cloth. Occasional brushing with a worn, soft-bristled toothbrush can help remove dirt from between crevices. For more resistant blemishes, use a weak solution of ammonia and water (about one part to four parts) and a soft brush. Remember to treat metal settings gently when you clean your diamonds as gold can scratch.

Regularly ask your jeweler to make sure your diamonds sit tight in their settings to help prevent stones from falling out. A jeweler can also clean diamonds and gemstones with steam or ultrasound, though ultrasound can worsen internal fissures or flaws.

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GEMSTONE BUYING GUIDE

From rubies and sapphires to emeralds, gemstones add a splash of color to any jewelry collection and make great gifts for birthdays and anniversaries.

• Select Emeralds, Rubies, and Sapphires
• Evaluate Gemstone Color
• Buy Birthstones
• Maintain Your Gemstones
• Find Gemstones on eBay
• Buy Gemstones with Confidence

Select Emeralds, Rubies, and Sapphires

The three most widely-recognized non-diamond gemstones, sapphires, rubies, and emeralds, typically have some mineral traces or inclusions. You'll have a hard time finding rare (and very expensive) slightly-included or flawless gems. But you shouldn't worry too much; the jewelry industry considers even moderately-included gems "desirable."

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EMERALDS

Emerald hues range from yellow-green to blue-green. The most valuable stones are pure green. Considered the birthstone of the month of May, emeralds are also the anniversary gemstone of the 20th, 35th and 55th year of marriage. Emeralds lend themselves to elaborate carving and inscription because of their composition.

RUBIES

Traditionally considered the most valuable gemstone, rubies are the birthstone for the month of July and traditional 15th and 40th year anniversary presents. Ruby hues range between orange-red and purple-red.

• Oil & resin gemstone treatments: Gemstones, like emeralds and rubies, are frequently treated with oils and resins. Time and excessive heat can cause this filler to break down, requiring the gems to be professionally repaired.
• Gemstone heat treatment: Sapphires and rubies frequently are treated with heat. This process permanently enhances color without changing the stone's structure.
• Chemical or "diffusion treatment" for gemstones: On a less frequent basis, gems can be treated with cobalt, beryllium or other elements to enhance apparent color. However, this only changes the surface of the stone. A scratch can reveal the lighter hue underneath.

Evaluate Gemstone Color

When shopping for gemstones pay close attention to color. Unlike diamonds, different gemstones have different densities, rendering carat weight useless as an accurate measurement of size (to determine size, look at diameter, length, and width measured in millimeters). In other words, a lighter weight gem with even color may be more valuable than a heavier gem. Also, the color of good stones can mask inclusions more than in diamonds. You should look for three aspects of color:

• Hue: Hue is the unique color of the gemstone. While almost all stones have some shades of other colors, the most valuable stones present the purest hue: red rubies, green emeralds and either blue or pink sapphires.
• Tone: Tone is the depth of a gemstone color, from colorless to black. Tone is described on a scale that ranges from light to medium to dark. The most valuable stones range from medium-light to medium-dark
• Saturation: Saturation is the purity of the color throughout the gemstone. A gem that is free of gray or brown hues is said to be strongly saturated and is more valuable than a stone with lower saturation. Saturation often determines the cut of a gemstone. A high-quality gem cut delivers an even color throughout the stone and exposes the fewest inclusions.

Stones with a deep, saturated color look best and are most valuable with a shallow cut that allows consistent, bright color. A stone with less color saturation should be cut more deeply to let more light into the stone for sparkle. Symmetry (the balance of the gem's facets) and polish (the surface smoothness of a gem) also affect the sparkle of the gem and can enhance or detract from its value.

Maintain Your Gemstones

Make sure your gemstones stay in tip-top shape with a few simple steps. Jewels need space to remain free of chips. Store gems individually in soft cloth pouches and prevent jewels from bumping against one another.

Clean your gemstones

Dust, skin oil and other unclean substances can cause your diamond or gems to lose their sparkle. Clean your gems from time to time in soap and water. Air dry and polish with a soft cloth. Occasional brushing with a worn, soft-bristled toothbrush can help remove dirt from between crevices. Remember to treat metal settings gently; gold can scratch. For more resistant blemishes, use a weak solution of ammonia and water (about one part to four parts) and a soft brush.

Take your gemstones to the jeweler

Annual checkups with a jeweler help keep your gemstones clean and properly situated in their settings. A jeweler can clean gems with steam or ultrasound, though ultrasound can make internal fissures or flaws worse. Although four-prong, six-prong, and low-profile channel or bezel settings offer your gemstone more protection than other settings, you should ask your jeweler to make sure your gemstones are still sitting tight in their settings to help prevent stones from falling out.

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PEARLS

Determine Which Type of Pearl You Need

When a small foreign object gets introduced into the body of an oyster or mollusk the organism produces a soft coating of calcium carbonate (nacre) around it, creating a pearl. Small foreign objects don't wander into mollusks very often so pearl cultivators insert microscopic objects into the organisms to create cultured pearls. You'll find four popular types of cultured pearls on eBay:

• Freshwater cultured pearls: Affordable freshwater cultured pearls originate in the freshwater lakes and rivers of China. They often have an asymmetrical shape, medium to high luster, and measure between 3.5 mm and 7.0 mm. Freshwater cultured pearls are mostly white, but can have a pink or rose tint.
• Tahitian cultured pearls: Tahitian cultured pearls have a unique black to grayish-green color. The large pearls, ranging from 11 mm to 13 mm, are farmed on the volcanic atolls and reefs of Tahiti. They are mostly round in shape and have a rich, high luster. Tahitian cultured pearls tend to cost more than other types of pearls based on their scarcity and unique look.
• Akoya cultured pearls: Akoya cultured pearls are a type of saltwater pearl from China and Japan. They have round, symmetrical shape with few blemishes and measure between 6 mm and 8.5 mm. Akoya cultured pearls have a higher luster than freshwater pearls, average pricing, and a light color that ranges from cream to white/pink.
• South Sea cultured pearls: Large South Sea cultured pearls (up to 13 mm), farmed in Australia, Indonesia, and the Philippines, range in color from white to black. They can have a perfectly round to slightly asymmetrical shape and medium to high luster. Price varies depending on luster.

Judge Pearl Quality

Six factors determine the value of pearls:

1. Pearl luster: Luster describes a pearl's shininess. The higher the luster, the greater the pearl's value.
2. Pearl nacre thickness: The depth of the nacre, a pearl's external layer, is a measure of pearl quality. Generally, bigger pearls have thicker nacre layers and greater luster. Thin nacre can be prone to chipping and peeling.
3. Pearl surface texture: Natural pearls can have a wide variety of abrasions. Minimal flaws do not severely detract from a pearl's value. However, more obvious surface imperfections will reduce a pearl's value. Drilling holes and stringing pearls on a necklace or mounting pearls can help deemphasize such imperfections.
4. Pearl color: The color of pearls is called "body color." Color is not a significant factor in determining a pearl's value as pearls can be found in gray, blue, gold, pink, white, black, and all shades of cream. Pearls can also be dyed, though reputable sellers should alert buyers of any such treatments. Some pearls have a secondary color or overtone. For instance, a white pearl may have a blue or pink tint upon closer inspection.
5. Pearl shape: Pearl shape can vary widely. Perfectly round pearls tend to command the greatest prices. Drop pearls and pear-shaped pearls can be particularly suited for earrings. Many jewelers use irregular baroque pearls as accents in jewelry.
6. Pearl size: Similar to diamonds, larger pearls are more expensive. Round pearls are measured according to their diameter in millimeters; baroque pearls by length and width.

Maintain Your Pearls

Pearls are not as hard as mineral gemstones. When dressing, put on pearls only after applying hairspray, cosmetics, perfume or other potentially harmful substances that might stain them. To prevent chipping, pearl jewelry should be stored in soft cloth, away from other jewels.

Clean your pearls The oils from your skin actually help keep pearls moist, so even soapy water is unnecessary for cleaning pearls. Never clean pearls with any type of solvent or abrasive. To best maintain them, wipe them after use with a soft cloth, like those used for eyeglasses.

Know when to restring your pearls It is recommended that you restring pearls every few years as strings can wear down and break if not maintained.

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