Pearls: The Treasures of the Sea

Pearl, the birthstone for June, is among the most timeless, classic and treasured of all gems. Throughout history, these noble gems have been associated with wisdom, wealth, purity, romance and mystery. The ancient Egyptians were buried with them. In Rome, pearls were considered the ultimate symbol of wealth and status. The Greeks prized them for their beauty and association with love and marriage. Medieval knights wore them in battle as a talisman against injury. And during the Renaissance, some European countries banned all but nobility from the right to wear them.
It's hard to believe that such a luscious, beautiful gem comes from such humble origins. A natural pearl starts out as a grain of sand or microscopic worm that works its way into an oyster and cannot be expelled. To protect its soft body from this irritant, the oyster secretes a smooth, hard crystalline substance called nacre. Layer upon layer of nacre coats the foreign object and hardens, ultimately forming a pearl. In general, the thicker the nacre, the richer the "glow" of the pearl - which can greatly enhance its value.
Although early pearl gathering depended on divers braving the oceans' depths to retrieve these treasures, the vast majority of pearls today are grown, or cultured, on pearl farms by surgically inserting a small shell bead, or nucleus, into the mantle of an oyster.
Even though pearls are harvested en masse on pearl farms, producing a quality pearl is an extremely rare event. It is estimated that half of all nucleated oysters do not survive - and of those that do, only 20% bear marketable pearls.
Pearls - the recommended gift for couples celebrating their third and 30th wedding anniversaries - are cultured in a variety of sizes, shapes, colors and kinds:

* Akoya pearls are the classic round pearls found in most quality pearl jewelry. They are mainly grown in the waters off Japan. They come in a range of hues, including white, cream, pink and peach.
* White South Sea pearls are grown in Australia, Indonesia, the Philippines and other areas of the South Pacific and are prized for their large size.
* Tahitian pearls, grown in French Polynesia, can be very large and come in a range of natural colors from gray to black to green to purple. Because of their large size and unique dark colors, they command very high prices.
* Mabe pearls, grown in Japan, Indonesia, French Polynesia and Australia, are usually flat-backed because they form against the inside shell of the oyster rather than within the oyster's body. They are often used in earrings and rings.
* Freshwater pearls are grown in bays, lakes and rivers primarily in Japan, China and the United States. They are often irregularly shaped, of various colors, and are less lustrous than saltwater cultured pearls hence, they are substantially cheaper.

When shopping for pearls, the five factors that determine value are luster (surface brilliance); surface cleanliness (absence of spots, bumps or cracks); shape (generally, the rounder the pearl, the higher its value); color (pearls come in virtually every hue of the rainbow, and a few others, too); and size (the average pearl sold is 7-7.5 millimeters, but these gems can be as small as 1 millimeter or as large as 20 millimeters). High-quality pearl strands will feature pearls well-matched in these characteristics.
Because pearls are soft, ranking only 2.5-4.5 on the Mohs scale for hardness, they require special care. Natural oils from the skin, as well as hair spray, lotions and cosmetics, can dull their luster. Like other jewelry, they should be cleaned with a soft damp cloth and stored in cloth or cotton away from other jewelry to prevent scratching. Also, avoid allowing your pearl to come in contact with harsh chemicals, which can erode its surface. And if worn frequently, pearl necklaces should be brought to a jeweler once a year for re-stringing to prevent strand breakage.

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Opal: The Queen of Gems

Opal, the birthstone for October, is one of nature's most prized gems. The stone - which also happens to be the recommended jewelry gift for couples celebrating their 14th wedding anniversary - was mined by eastern Europeans, the Aztecs and the ancient tribes of Central Africa. Opals have been featured in the crown of the Holy Roman Emperor and the crown jewels of France. They were mentioned in the plays of Shakespeare and the novels of Sir Walter Scott. Napoleon gave an opal to Josephine. Queen Victoria gave them out as wedding gifts.
One of the reasons this gem has been so revered is because of its supposed mystical powers. Scandinavian women wore opals in their hair to prevent it from going gray. The Arabs thought opal would ward off lightning and grant invisibility to its wearer. Other powers ascribed to the gem include the ability to grant vigor, aid the heart and kidneys and protect against fainting and infection.
Worshipped by the Romans as a symbol of hope, fidelity, purity and good luck, opal is sometimes called the "queen of gems" because the stone can flash patterns of color representing every hue of the rainbow.
This "play of color" is one of opal's signature characteristics. The gem is found in a range of hues, including white opal (the most common); black opal; "boulder" opal (black opal with iron oxide); crystal or water opal, which is transparent; and fire opal, which has a yellow to orange to red body color.
The vast majority of the world's opal supply comes from Australia. Black opal is the rarest variety and therefore the most valuable. White opal is also mined in Brazil. Fire and crystal opal can be found in the United States (Nevada) and Mexico.
Brilliance of color and color pattern are critical in determining the value of opal. Opals with strong flashes of red fire are generally the most prized. Stones with blue or green flashes are more common and subsequently less valuable. Stone size also helps determine price, since the gem is very rare in larger sizes. Prices can vary from a few dollars per carat for common white opal to more than $1,000 per carat for fine black opal. Most stones are not faceted and usually cut into rounded cabochons to enhance color play.
Perfect natural opals are extremely rare and expensive. Many are treated to enhance their appearance. One common technique is to place the opal in a sugar solution and then in sulfuric acid, which blackens body color and makes the play of color more pronounced. Other treatments include applications of colorless oil, wax and resin, plastic, or synthetic resins and hardeners to fill cracks and improve durability.
With a hardness of approximately 5.5 on the Mohs scale, opal is relatively fragile, and care should be taken not to scratch, chip or crack it. To clean opal, use a soft cloth moistened with olive oil. Do not use chemical or mechanical cleaners. Also, avoid heat and dry conditions that could dehydrate and crack the stone. Avoid impacts.

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Garnet: The Gem for All Seasons

Garnet, the birthstone for January, is one of the most versatile stones on the market. It comes in a rainbow of colors, from deep red to tangerine orange to lime green to pale pink, as well as purple, gold and brown.
The name garnet most likely was derived from the pomegranate, a fruit whose deep red-purple color resembles some varieties of garnet. Many ancient pieces of garnet jewelry are studded with tiny red gems that look like a cluster of pomegranate seeds.
Garnet is found all over the world, including Africa, Australia, Eastern Europe, the Middle East, North America, South America and Southeast Asia. There are garnets that change color in different light, translucent green garnets that look like jade, and garnets that display a faint four-rayed star. Even though this exciting gem has been mined for thousands of years, new deposits have been found in the last decade.
This stone is actually part of a family of gems with mineral and color differences that include rhodolite, malaya, demantoid, grossular, hessonite, spessartite, almandine, mandarin, and combinations of these varieties.
Almandine, the most common type, is dark red to brownish red. Pyrope is blood red. Rhodolite, one of the most popular varieties, ranges from pink to purplish red and is mined in Africa, India and Sri Lanka. Malaya, a mixed variety found in Tanzania and Kenya, ranges from orange to gold. Tsavorite is bright yellow green to grass green and is also mined in Tanzania and Kenya. Demantoid is primarily found in Russia. Hessonite and spessartite mostly come in golds, oranges and browns. Mandarin is a bright orange type of spessartite recently found in Namibia. Grossular is available in pinks, greens and yellows.
As the most common types of garnet, almandine and pyrope are also the most affordable. But tsavorite and demantoid are quite rare and can cost several thousand dollars per carat depending on size and quality. Bright colors usually command higher prices than gems with light or dark hues. The stone also is available in a variety of sizes, depending on the type of garnet. Larger stones are available in the more common types and exceedingly scarce in more valuable tsavorites and demantoids.
Throughout history, garnets have been prized for their rich hues and supposed mystical properties. The stone was a favorite of ancient Egyptian jewelry artisans. Demantoid garnet was used lavishly by the Tsars of Russia. Travelers carried the gem to protect them against accidents. The gem was thought to protect its wearer from a range of ailments, ward off evil spirits, spark creativity and dispel anger. The stones are also said to light up the night and protect their owners from nightmares. Noah used a garnet lantern to navigate the Ark through 40 days and nights of torrential rain.
Garnet's various types range from 6-7 on the Mohs scale of hardness, which means that the stone is susceptible to nicks and cracks caused by impact.
To clean garnet, use warm soapy water and a soft brush. Ultrasonic cleaning is safe for most types of garnet except demantoid. Avoid steam cleaning.
Garnet is the recommended gift for couples celebrating their second wedding anniversary.

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Emerald: The Symbol of Spring

Emerald, May's birthstone, has been prized for thousands of years for its lush green hues and rare beauty. Throughout the ancient world, emerald symbolized eternal hope, rebirth and the arrival of spring - and some cultures believed the gem rewarded its owners with love, intelligence and eloquence as well.
The ancients ascribed numerous magical and mystical properties to this most precious of green gems. In ancient Rome, for example, emeralds were believed to have a soothing effect on the soul. Modern scientists have since shown this myth to have some basis in fact: tests indicate that the human eye is more sensitive to green than any other color. Middle Age seers used emeralds to foretell the future, as well as to ward off evil spirits and cure ailments ranging from bad eyesight to infertility. The stone was also said to improve memory and bring great wealth to its wearer.
Derived from the Latin word for green, "smaragdus", emerald is also the traditional gift of choice for couples celebrating their 20th and 35th wedding anniversaries.
The finest emeralds have traditionally come from Colombia; both the Incas and Aztecs mined rich emerald deposits in the rugged Andes Mountains. But Russia's Ural Mountains also have produced top-quality gems. Brazil is by far the world's largest producer of emerald, with a wide range of quality. Other sources for the stone include Afghanistan, Australia, India, Pakistan, the United States, Zambia and Zimbabwe.
Emeralds come in a variety of light and dark shades of green - and often with subtle background hues of other colors like yellow, blue, brown or gray. Generally, the purer and richer the green, the more valuable the emerald. The gem ranks 7.5-8 on the Mohs hardness scale. This means that emerald, while relatively hard, can still be scratched, chipped or split fairly easily. Most emeralds have numerous flaws, or "inclusions", which weaken their structure. Flawless emeralds are exceptionally rare, and therefore command great prices (in some instances, higher than diamonds).
When shopping for emeralds, keep in mind that the gems are judged by size, color, clarity and cut (although because of the stone's penchant for inclusions, a lesser clarity is acceptable - as long as light is still reflected through the gem). Color is extremely important, and is broken down into three considerations: hue (the basic color of the stone, including any tints other than green); tone (the "depth" of color, ranging from "light" to "dark"); and saturation (the purity of the green and the level of other hues, if present).
Fissures, or cracks, are common in emeralds. Try to avoid those that penetrate too deeply into the stone, thus making it more susceptible to splitting.
Like most gemstones in the market today, emeralds are usually treated in some way to remove surface flaws and enhance color. The most common (and acceptable) technique is to oil the stone with a green-tinted oil to fill in surface cracks. The oil hardens and strengthens the stone, and improves its green color as well.
In caring for your emerald, avoid ultrasonic cleaners that can remove the oil, or harsh cleansers that can damage its relatively soft surface. Clean with a soft, damp cloth and warm water, and a soft bristle brush if needed. The gem has been known to crack when exposed to extreme temperatures, so keep this in mind when wearing your emerald. Regularly check that setting prongs aren't loose or cracked, and have a jeweler re-oil every few years.

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Blue Topaz: Birthday Blue

Blue topaz has become one of the most popular gemstones on the market today, due to its clarity, durability, availability and affordable cost. Yet it is a shade of topaz rarely found in nature. The stone's watery blue color is most often created through a combination of heat treatment and irradiation.
Topaz is one of the well-known pegmatite minerals that also includes beryl and tourmaline. Blue topaz is the birthstone for December - and is also the recommended gemstone for couples celebrating their fourth wedding anniversary.
Blue topaz has a definite, uniform color ranging from sky blue to Swiss blue. It is sometimes confused with the more costly aquamarine - yet whereas aquamarine sometimes has a greenish-blue or bluish-green tint, blue topaz will always look blue or bluish gray. The one exception is for surface-enhanced topaz, a process introduced in 1998 that enhances the stone's appearance and brings out colors such as blue to greenish-blue to emerald green.
Most blue topaz starts life as a colorless or slightly tinted topaz from places like Brazil, Mexico, Nigeria, Sri Lanka and China. It is then irradiated (to incite the color change) and heated (to stabilize the change). The result is a permanent aqua shade. To get deep blue color out of topaz, treaters use neutron bombardment in a nuclear reactor and market the final product under the name "London blue." In fact, neutron bombardment is the only means by which to produce smaller calibrated stones with deep color.
Despite the stone's exposure to irradiation, experts say it poses no health hazard whatsoever to the wearer.
In addition to blue, the stone comes in a variety of colors, including golden yellow, orange-yellow, reddish-orange, sherry red, deep pink, honey brown, light green, and many shades in between.
Topaz holds the distinction of being the gemstone thought to have the widest rage of curative powers. According to legend, the stone can dispel enchantment and improve the eyesight. The ancient Greeks believed that it had the power to increase strength and make its wearer invisible in times of emergency. Topaz is also said to change color in the presence of poisoned food or drink. Throughout history, different cultures have believed that the stone could cure insomnia, asthma and hemorrhages; bring friendship; promote patience and a pleasant disposition, and ensure fidelity. To the ancients, it was also a symbol of love and affection and was even thought to ward off sudden death.
With a ranking of "8" on the Mohs scale of hardness, blue topaz is exceptionally strong and durable and well-suited to everyday wear. However, it should be protected against hard blows that can split, crack or chip it.

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Aquamarine: Gem of the Sea

Aquamarine derives it name from the Latin term for seawater - and one look at this elegant gem's blue hues easily explains why.
According to legend, aquamarine was the treasure of mermaids and had the power to keep sailors safe at sea. It was also thought to possess a number of other mystical properties, including the ability to help couples smooth out their differences; protect against the wiles of the devil; cure headaches, insomnia and other ailments; quicken the intellect; and attract new friends. It is the symbol for youth, hope, health and fidelity.
It is also the birthstone for March and the recommended gem for couples celebrating their 19th wedding anniversary.
A variety of the mineral beryl, like the emerald, aquamarine is found in many exotic places around the world, including Afghanistan, Angola, Kenya, Madagascar, Mozambique, Nigeria, Pakistan, Sri Lanka, Russia, Zambia and Zimbabwe. But most of the gemstones available in the market today come from Brazil.
Aquamarine is found in a range of blue shades, from pale pastel to greenish-blue to deep blue. Deeper colors are unusual in smaller sizes; generally, it takes a larger stone to hold a darker shade. The most prized aquamarines are those displaying a deeper, pure blue, with no green tints. These are rarer and therefore more valuable. But if you prefer those with a greenish hue, you should be able to get them for a bargain price.
Like with any gem that is pale, aquamarines should be "eye clean" (no inclusions visible to the naked eye), since internal flaws are more noticeable in a pastel stone. This shouldn't be much of a problem - unlike its emerald sister, aquamarine is known for being relatively free of inclusions. This is why aquamarines are frequently cut with large step facets to show off their flawless surfaces. The most popular cuts for aquamarine are oval and emerald.
Settings for aquamarine can also safely expose more of the gemstone than is possible with emerald. Aquamarine's tendency toward having few inclusions makes it less susceptible to nicks or cracks than many other gems. With an "8" ranking on the Mohs hardness scale, the stone is very durable and can stand up to everyday wear. Its clear, pale brilliance makes it an appropriate stone for all types of jewelry - and it combines well with all jewelry metals and is flattering to most skin tones.
Aquamarine is commonly heat-treated to permanently remove green overtones. Unlike its sister stone the emerald, aquamarine generally isn't plagued by surface fractures - which means the stone isn't usually treated with fillers, resins or oils. Even so, avoid mechanical cleaners. To clean aquamarine, use warm soapy water.
The largest known aquamarine is a 243-pound stone found in Brazil in 1920. It was cut into many smaller stones and a 13-pound uncut piece resides in the American Museum of Natural History. Another noted aquamarine is an 879.5-carat flawless, step-cut, sea green stone on display in the British Museum of Natural History.

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Amethyst: The Color for Kings

Amethyst has long been a favorite gem of kings and queens for its royal purple hues. The gem, the most precious member of the quartz family, exhibits color ranging from pale lilac to deep purple. Amethysts are featured in the British Crown Jewels and were worn by Catherine the Great as well as Egyptian royalty.
Through the ages, various special properties have also been prescribed to amethyst. The Greeks and Romans considered it a strong antidote against drunkenness and drank wine from goblets carved out of the gem. Leonardo Da Vinci wrote that amethyst could dissipate evil thoughts and quicken the intelligence. The stone also is supposed to bring peace of mind to the wearer and prevent fatal poisoning.
In some legends, the stone also represents piety, celibacy and dignity. In Tibet, for instance, amethyst is considered sacred to Buddha and rosaries are often made from it. In the Middle Ages, the gem was an important ornamentation for the Catholic Church and other religions. In fact, it was considered the stone of bishops, and they still often wear amethyst rings.
The birthstone for February, amethyst is an extremely popular gem for jewelry because of its regal color, variety of sizes and shapes, affordability and wide range of hues. It also is the recommended gem for couples celebrating their sixth wedding anniversary.
The stone is mined in Brazil, Uruguay, Bolivia and Argentina, as well as in Zambia, Namibia and other African nations. Very dark amethyst in small sizes also is mined in Australia. But the ideal for fine quality amethyst was set by a Siberian variety, often called Russian or Uralian amethyst, which is now considered a defunct source.
Generally, South American amethyst tends to come in larger sizes than African amethyst. But the African variety has a reputation for having deeper color intensity and is therefore considered more valuable. The African version also is harder to come by than amethyst mined from South America. Most of today's amethyst comes out of Brazil.
The finest and most valuable amethysts are very clear, with very deep color (and they sometimes exhibit reddish or rose overtones). Some stones are so oversaturated with color they have areas that are blacked out, which can negatively impact their value.
Amethyst is available in a wide range of calibrated sizes and shapes, including many fancy cuts. Large fine stones are sold in free sizes but generally the stone is cut in standardized dimensions. Paler shades, sometimes called "Rose of France", were common in Victorian jewelry. Banding - darker and lighter zones of color - is also a common occurrence. Occasionally, amethyst is even found combined with its sister quartz citrine into a single stone called ametrine.
The most common enhancements to amethyst are heat and irradiation. The stone, which ranks a 7 on the Mohs hardness scale, is considered durable enough for everyday wear. However, care should be taken not to expose the gem to excessive amounts of bright sunlight, as this can cause its color to fade.

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Citrine: Versatile, Affordable and Golden Yellow

Citrine is the most affordable of all the earth-toned gemstones, thanks to its durability and availability. It has become increasingly popular with budget-minded women looking to expand their work and leisure jewelry wardrobes.
Citrine, a form of quartz, derives its name from the French word for lemon, "citron." It is available in a range of golden hues from lemon to straw to sun yellow to gold, as well as oranges, browns, and deep madeira red. It is generally more inexpensive than amethyst and is also available in a wide range of calibrated sizes and shapes, including very large sizes.
Citrine's lively colors can brighten almost any jewelry style, and it blends especially well with yellow gold. Its low cost makes it an ideal stone for popular free-form fancy cuts for one-of-a-kind and customized pieces. And good cut is as important in determining citrine's quality as it is for more expensive yellow counterparts, such as yellow sapphire.
As with other stones, citrine in very large sizes (above three carats) in rich, deep colors has always been rare and therefore the most valuable form of the gem. Although this stone's dark orange and red shades traditionally have been the most prized, its bright lemony hues have become very popular in recent years because they mix better with pastel colors.
In ancient times, citrine was carried as a protection against snake venom and evil thoughts. It was also thought to give calmness and mental balance to its wearer.
Citrine is the birthstone for November, as well as recommended jewelry gift for couples celebrating their 13th wedding anniversary.
Most citrine is mined in Brazil. Supplies are most plentiful in the Brazilian state of Rio Grande do Sul, particularly from the Serra mine. The Ira' mine also produces large quantities of the gem.
These stones generally start life as either smoky quartz or amethyst geodes. Heat treatments first turn them clear and then give them a permanent color ranging from yellow to brownish red.
Sometimes citrine is referred to as topaz quartz, which is incorrect. The name refers to the color, which is sometimes similar to topaz. But since topaz is a separate mineral, the name could be confusing and should not be used.
Occasionally, Mother Nature combines the colors of amethyst and citrine into a single gemstone called ametrine.
With a ranking of "7" on the Mohs scale of hardness (from 1-10, with "10" representing a diamond, the hardest mineral on earth), citrine has excellent durability and is suitable for everyday wear. However, since much of the citrine on the market today has been heat treated to improve its color, it should be kept away from prolonged exposure to strong light or heat.

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Peridot: Soothing Green

Peridot, the gem form of the mineral olivine, traces its jewelry roots back more than 3,500 years. It was first mined by the ancient Egyptians on the island of Zebargad in the Red Sea. Zebargad was known as the "serpent isle" because it was infested with snakes that interfered with mining activity until one Pharaoh finally had them all driven into the sea.
Found in various shades of green, peridot is most prized in lime hues. The Romans called peridot "evening emerald" because its green color was said to glow at night. The gem was also used to decorate medieval churches and was most likely carried back to Europe by the Crusaders. Large peridots of more than 200 carats in size adorn the shrine of the three magi at the Cologne Cathedral in Germany.
Small crystals have been found in volcanic rock - in fact, Hawaiian legend called peridot the divine tears wept by Pele, goddess of the volcano. Samples of the gem also have been discovered in meteors that have fallen to earth.
The ancients believed that peridot had the power to ward off evil spirits, nightmares and enchantments. It was also used as a medical remedy to treat asthma and other ailments. Its power was considered most potent when the stone was set in gold. Peridot was also said to strengthen any medicine drunk from goblets carved from the stone.
Most of today's peridot is mined by Native Americans on the Carlos Reservation in Arizona. It is also mined in Brazil, China, Egypt, Germany, Hawaii, Italy, Norway, Myanmar, and Sri Lanka. A new deposit was discovered in Pakistan in 1994, yielding some of the finest peridot ever seen. Numerous fine, large crystals were discovered, including one stone of more than 300 carats.
Peridot is readily available in a range of sizes, shapes and color hues. The finest stones are eye clean and have a deep, lime green color. Because inclusions are common, clarity is an extremely important factor when buying peridot.
Its relative affordability and lively green color has made it a popular substitute for those who cannot afford emeralds. The birthstone for August, peridot is also the recommended gem for couples celebrating their 16th wedding anniversary.
When shopping for peridot, keep in mind that it is relatively soft (6.5 on the Mohs hardness scale) and should be spared rugged, regular wear if mounted in a ring. This is why the gem is more often used as a sidestone for more expensive gems than as the center stone. It is also highly sensitive to rapid temperature changes and can lose its polish if brought into contact with hydrochloric or sulfuric acid.
Peridot is occasionally treated with colorless oil or wax to improve its appearance. Surface fractures are sometimes filled with a colorless resin that hardens. If done properly, these treatments should remain stable.
Fine large specimens of the stone are on display at the Smithsonian Institution in Washington, D.C.; the Diamond Treasury in Moscow; and the Geological Museum in London.

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Ruby: the King of Gems

Perhaps no gemstone has been as prized throughout history as the ruby. Celebrated in the Bible and in ancient Sanskrit writings as the most precious of all gemstones, rubies have adorned emperors and kings and inspired countless legends and myths with their rich, fiery hues.
As the ultimate red gemstone, rubies have symbolized passion and romance for centuries. Ruby is the birthstone for July and is also the recommended gem for couples celebrating their 15th and 40th wedding anniversaries.
Also the color of blood, the stone is symbolic of courage and bravery. Warriors were said to have implanted rubies under their skin to bring them valor in battle and make them invincible. The stone has also been used as a talisman against danger, disaster, to stop bleeding, and a number of other ailments. Its intense color was thought to come from an undying flame inside the stone - or, as some legends would have it, a piece of the planet Mars.
Ruby is the red variety of corundum, a sister of sapphire. Like sapphire, ruby rates a "9" on the Mohs scale of hardness, making it the second hardest material known after diamonds.
The most valuable rubies come from Myanmar (formerly Burma), but they are mined throughout Southeast Asia. Good quality stones come from Thailand, Sri Lanka, and Vietnam. Kenya and Tanzania also are becoming more important as mining sources for ruby. But while the color of the stones from East Africa rivals the world's best rubies, most of these stones are fraught with inclusions that diminish their transparency and value. However, the East African stones are displayed to full advantage in cabochon cuts and have done well in the mass jewelry market. Meanwhile, Afghanistan, Pakistan and Russia have all produced occasional top-quality rubies, but the rough terrain in these areas has made mining difficult.
The most important factor to consider when buying a ruby is its color. It comes in a variety of shades ranging from purplish- and bluish-red to orange-red. Like sapphire, there is also a translucent variety of ruby that can display a six-point star when cut in a smooth domed cabochon cut.
The finest rubies are intensely saturated, pure red with no overtones of brown or blue. After color, the factors that influence value are clarity, cut and size. Rubies that are clear with no visible inclusions are more valuable than those with visible internal flaws.
Rubies are readily available in sizes up to 2 carats, and because of their intense color and durability, they make excellent accent stones. Larger sizes can be obtained, but top-quality rubies are rarer and more valuable than colorless diamonds - particularly in sizes above 5 carats. For instance, a 16-carat ruby sold at auction for $227,301 at Sotheby's in 1988. A 27.37-carat Burmese ruby ring sold for $4 million at Sotheby's in Geneva, Switzerland, in May 1995 - an astounding $146,145 per carat. In contrast, none of the D-color, internally flawless diamonds over 50 carats sold in the last decade can match this value per carat.
Rubies are rarely found perfect in nature - which is why many are heat-treated to intensify or lighten their color or improve their clarity. Heat enhancement is a permanent, stable process. Some rubies also have surface fractures and cavities that are filled with glass-like materials to improve their appearance. This filler may break, fall out or wear out over time if exposed to heat, strong abrasives or constant impact. For both treated or untreated stones, the safest cleaning method is to just use soapy water or a mild commercial solvent and a brush.

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Sapphire: The Jewel of the Sky

Sapphire has been sought after for thousands of years as the ultimate blue gemstone. The ancient Persians believed that the earth rested on a giant sapphire that gave its blue reflection to the sky, hence the Latin name "sapphiru", which means blue.
The gem has long symbolized faith, remembrance, and enduring commitment. According to tradition, God gave Moses the Ten Commandments on tablets of sapphire, making it the most sacred stone. This supposed "divine favor" is why sapphires often were the gem of choice for kings and high priests throughout history. In fact, the British Crown Jewels contain a number of notable sapphires. Prince Charles even gave Princess Diana a sapphire engagement ring.
Sapphire is the birthstone for September. It is also the recommended gem for couples celebrating their fifth and 45th wedding anniversaries.
Both sapphire and its sister stone, ruby, are part of the corundum family, one of the strongest minerals on earth. The stone is mined in many parts of the world, including Australia, Cambodia, China, Kashmir, Kenya, Madagascar, Myanmar, Nigeria, Sri Lanka, Tanzania, Thailand, the United States and Vietnam. Sapphires from Kashmir and Myanmar are rarest and most prized because of their vivid blue, velvety look.
Although sapphire is virtually synonymous with blue, the stone also comes in a variety of fancy colors that includes colorless/white, pink, yellow, peach, orange, brown, violet, purple, green and many shades in between (except red, because a red sapphire would be called a ruby). Some sapphires that are cut into a cabochon (dome) shape even display a six-rayed white star. These are called star sapphires, and the ancients regarded them as powerful talismans that protected travelers.
Like other gemstones, color is the main determining factor when judging the value of a sapphire. As a rule, the most valuable sapphires have a medium intense, pure vivid blue color and hold the brightness of their color under any type of lighting. Any color undertones - usually black, gray or green - will reduce a stone's value. Although a pastel stone would be less valued than a deeper blue one, it would be more valuable than a stone considered too dark. In selecting your sapphire, keep in mind that the finest stones are "eye clean", with little or no inclusions (flaws) visible to the naked eye.
Sapphire is readily available in sizes of up to 2 carats, but gems of 5-10 carats are not unusual. The stone is most often cut in a cushion shape - a rounded rectangle - or an oval. But smaller stones are available in round brilliant cuts and a variety of fancy shapes, such as triangle, square, emerald, marquise, pear, baguette, cabochon and others.
Some of the more noted sapphires include the Logan Sapphire, a 423-carat cushion-cut stone from Sri Lanka currently in the Smithsonian Institution in Washington, D.C., and a 258-carat stone set in the Russian crown and kept in the Diamond Fund in Moscow.
With a hardness of 9 on the Mohs scale, sapphire is harder than any other gemstone except a diamond. This quality makes it extremely durable for everyday jewelry pieces subject to repeated impact, such as rings and bracelets. In general, sapphire can be cleaned with soapy water or commercial solvent and a brush.
It is estimated that about 90% of sapphires on the market today have been heated to maximize their color and clarity. This process is permanent and completely stable. Perfect natural, untreated gems are exceptionally rare and very expensive. Some colorless or pale stones are treated with chemicals (diffusion treated), which improves the surface color only. This could create a problem if the stone is ever chipped or nicked and needs to be recut or repolished. In addition, some fancy colored sapphire is irradiated to give it a more intense shade. These effects are temporary and can fade in light or heat.

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