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Gemstone Information

James Avery selects the best quality natural or lab gemstones based on three qualities: beauty, rarity, and durability. Beauty can be measured by the gemstone’s color, clarity and cut. Rarity is determined by the scarcity of the gem’s occurrence in nature or in the marketplace. And durability is based on the hardness, toughness, and stability of the gem. James Avery does not use any imitation gemstones.

Carats, Shapes and Sizes

Carats are a measure of weight in gemstones. Due to variations in the chemical composition and the density of various types of gemstones, a one carat (1.00 ct.) stone will vary in size depending on the type of gemstone. For instance, the density of a topaz is greater than the density of a peridot. Therefore, the same weight of a one carat topaz will physically be a smaller stone than a peridot of the same weight.

Gemstone sizes are usually given in carat weight (ct) or described in millimeters (mm). Some typical gemstone shapes and approximate weights for various sizes and shapes are shown below, although the exact size varies depending on the type of gemstone.

In addition to weight and size, the prices of finer gemstones typically vary depending on the shape, cut, degree of clarity, and the tone and color of each gemstone.

Natural Gemstones

A natural gemstone is any stone that has crystallized in the earth unassisted by man before it is mined. Gemstones are rated on the Mohs Scale of Hardness which indicates the durability of the stone in jewelry. Minerals are ranked from the softest (1 for talc) to the hardest (10 for diamond).

Lab Gemstones

The first lab gemstone was produced in 1902 in Paris, France by a chemist named Louis Verneuil. A gemstone that is grown in a laboratory is not imitation or artificial, and is carefully crystallized over time. It has essentially the same optical, physical and chemical properties as a natural gemstone. Only a trained gemologist can tell them apart.

Natural gemstones are crystals formed by heat and pressure within the earth. A similar heat and pressure environment is created in the laboratory using the same natural elements. This process takes 10 to 14 months to complete.

Care and Cleaning of Your Gemstones

We recommend removing your gemstone jewelry before any vigorous physical activity to prevent loss or damage to the gemstone or setting. Most gemstones can be cleaned using a soft brush and a mild solution of lukewarm, soapy water. Do not put gemstones in an ultrasonic or steam cleaner, and avoid the use of harsh chemical dips. Use only those jewelry cleaners that are made specifically for cleaning delicate gems and pearls. When in doubt, allow a professional jeweler to clean your gemstone jewelry. For more information on how to care for and clean your James Avery Jewelry please visit our Care and Cleaning Information page.

Lab Alexandrite

Named after Alexader II, Czar of Russia, alexandrite was discovered on this ruler’s birthday in the early 1830’s. Alexandrite is the color changing variety of the mineral chrysoberyl. It changes from blue-green in daylight or fluorescent light to red-purple in lamp or candle light. It ranks 8.5 on the Mohs Scale of Hardness. The alexandrite is the modern birthstone for the month of June, and the anniversary gemstone representing the 15th and 55th year of marriage. Learn more about lab gemstones.

Amethyst

Amethyst is often considered the color of royalty because amethyst have long been treasured by ancient kings and emperors. They were once prized even more than diamonds. The amethyst is often referred to as the Bishop’s Stone, as it is worn by bishops to symbolize their triumph over worldly vices. Known as the gem of optimism and good fortune, amethyst reveals the positive vibrations surrounding those who wear it. Darker hues of amethyst are rarely enhanced to perfect their color, although some varieties do respond well to heat enhancement. Amethyst is a member of the quartz family, and it comes in a variety of purple shades of varying intensity–from pale lilac to deep purple. Amethyst is considered the most highly prized variety of quartz. Deposits for amethyst are found in Brazil, Uruguay, Madagascar, and regions of Africa. Do not expose amethyst to direct sunlight or extreme or prolonged heat which can cause damage and fading. It ranks 7 on the Mohs Scale of Hardness. Amethyst is the traditional birthstone for the month of February, and the anniversary gemstone representing the 6th and 9th year of marriage.

Aquamarine

Aquamarine is derived from the Latin word aqua marina, meaning seawater, and is known as the gem of the sea. This gemstone was believed to keep sailors safe and guard against storms, as well as bring hope, health, harmony, and happiness. The aquamarine is a member of the beryl family, and is known for its range of serene, oceanic shades from pastel to medium light blue-green or light green to deep blue. Many aquamarines are greenish when mined and cut. For those who prefer a purer blue, these gemstones are heated to enhance their blue color permanently. Its primary sources include Brazil and Africa. It ranks 7.5 to 8 on the Mohs Scale of Hardness. Aquamarine is the traditional birthstone for the month of March, and the anniversary gemstone representing the 18th and 19th year of marriage.

Blue Topaz

Blue topaz was once extremely rare; however, now it is one of the most available color topaz on the market. Most topaz found in nature are colorless. To get their blue color, a colorless topaz goes through a process called “irradiation” which is used to heat and color the stone blue. After the raw topaz is extracted from the earth and cut, it is irradiated to brown and then heated to sky blue. This enhancement process is permanent. Most blue topaz are mined in Brazil, Sri Lanka and Australia. do not expose blue topaz to direct sunlight, or extreme or prolonged heat which can cause damage and fading. It ranks 8 on the Mohs Scale of Hardness. It is the shared birthstone for the month of December with turquoise and blue zircon, and is the anniversary gemstone representing the 4th year of marriage.

Carnelian

The word Carnelian is derived from the Latin word carno, carnis meaning flesh, in reference to the color of the stone. Carnelian was used over 2,000 years ago during the Roman era to make signet rings for imprinting a seal with wax on correspondence or other important documents.

Carnelian is a member of the microcrystalline group within the quartz stone family. Heated to improve color, the Carnelian comes in an array of colors including shades of red, orange or brown colored Chalcedony. Sources are found in India, Brazil, and Uruguay. It ranks 6.5 to 7 on the Mohs Scale of Hardness. Carnelian is the anniversary gemstone representing the 17th year of marriage.

Chalcedony

Chalcedony was a treasured gemstone of the ancient world. The Victorians prized Chalcedony for carved cameos and intaglios because its fine texture allows for delicate and intricate workmanship. Chalcedony is a member of the quartz stone family. They are found in all 50 states and come in a wide variety of colors, tones and shapes. Most Chalcedony used in jewelry is color enhanced for a more consistent color. It ranks 6.5 to 7 on the Mohs Scale of Hardness.

Chrysoprase

Chrysoprase was a favorite of Frederick the Great of Prussia who loved the bright green color. Unlike most other green stones, which owe their color to chromium or vanadium, Chrysoprase derives its color from a nickel silicate. This gemstone is featured on many buildings in Prague in the czech republic, including the chapel of st. Wencelas. Deposits are found in Australia, Brazil, India, Malagasy Republic, South Africa, Russia, and the U.S. It ranks 6.5 to 7 on the Mohs Scale of Hardness.

Citrine

Citrine is named from the French word lemon, “citron”, since many citrines have a bright sunny yellow color. It also comes in hues of gold to orange brown shades. Brownish varieties are commonly heated and magically turn into the bright yellow or orange colors known as citrine. This enhancement method is permanent and will last for the life of the gemstones. During the romantic era of the 1800’s, citrine was said to symbolize joy and lightheartedness. Citrine is a member of the quartz family, and natural citrine deposits are mined mostly in Brazil, but also in Malagasy Republic, the U.S., Spain, Russia, France, and Scotland. Citrine should be kept away from prolonged exposure to strong light or heat which can damage and fade the stone. It ranks 7 on the Mohs Scale of Hardness. Citrine is considered an alternative to topaz as the modern birthstone for November.

Cultured Pearls

According to ancient Chinese legend, the moon holds the power to create pearls, instilling them with its celestial glow and mystery. Pearls have been treasured for their lustrous, creamy texture and subtle iridescent reflections since the dawn of mankind. Pearls are unique in the world of colored gemstones since they are the only gemstone formed within a living creature. because natural pearls are so rare and difficult to recover from the ocean’s depths, man invented the technique of culturing salt and freshwater pearls from mollusks carefully seeded with irritants similar to those produced by nature. Cultured pearls come in many beautiful colors including: gold, yellow, champagne, pink, peach, lavender, gray and black. Due to demand for perfectly matched white pearl strands, cultured fresh and saltwater pearls are often bleached to achieve a uniform color. They may also be polished in tumblers to clean and improve their luster. Dyes, heat treatment, and irradiation are sometimes applied to produce a wide range of hues such as yellow, green, blue, purple, gray, and black in freshwater and Akoya cultured pearls. Some South Sea cultured pearls are bleached to lighten their hue, but most South Sea and Tahitian cultured pearls are not subjected to enhancements to create or improve their color. Cultured pearls come in many shapes and sizes. The pearl ranks 3 to 4 on the Mohs Scale of Hardness. It is the traditional birthstone for the month of June, and the anniversary gemstone for the 3rd and 30th year of marriage. For more information on this gemstone, please refer to our Pearls information page.

Diamond

Derived from the Latin diamas meaning the unconquerable, diamond has maintained its position throughout history as a perfect icon for love and marriage. Although white is the most common color, diamond actually comes in a variety of colorful hues. The diamond is the only gemstone to rank 10 on the Mohs Scale of Hardness. It is the traditional birthstone for the month of April, and the anniversary gemstone representing the 10th and 60th year of marriage. For more information on this gemstone, please refer to our Diamonds information page.

Lab Emerald

The word “emerald” comes from a sanskrit word meaning “the green of growing things”. Legends gave emerald the power to make its wearer more intelligent and quick-witted. The first known emerald mines were in egypt, dating back to over 300 B.C. and into the 1700’s. Cleopatra was known to have a passion for emerald, and it was featured in many of her royal adornments. emerald is the most famous member of the beryl family. It ranks 7.5 to 8 on the Mohs Scale of Hardness. The emerald is the traditional birthstone for the month of May, and the anniversary gemstone representing the 20th and 35th year of marriage. Learn more about lab gemstones.

Garnet

Garnet traces its roots to the Nile Delta in 3100 B.C., where Egyptian artisans would craft the gemstone into beads or inlay them into hand-wrought jewelry. Legend proclaims this jewel had the ability to illuminate the night sky. Stories of The Ark say Noah used garnet as a lamp on his bow as he cast about on the ocean. Garnet received its name from the ancient Greeks because the color reminded them of the “granatum,” or pomegranate seed. The garnets in jewelry designed by James Avery are generally in the red-violet to red-brown color range. Garnets mainly come from the east Coast of Africa. Small deposits are also found in the U.S., Czech Republic, and India. It ranks 7 to 7.5 on the Mohs Scale of Hardness. Garnet is the traditional birthstone for the month of January, and the anniversary gemstone representing the 2nd year of marriage.

Lapis Lazuli

The beautiful blues in paintings from the Renaissance are thanks to the blue of lapis lazuli, the opaque blue gem material that was the secret ingredient in ultramarine, the valuable pigment that all the old masters used to capture the rich blues of the sea and sky and the robes of the Virgin Mary. The name, lapis lazuli is melange of languages. From the Latin, lapis means stone. From the Aracbic, azul means blue. Lapis lazuli us still mined at the deposits of the ancient world in Afghanistan. Today lapis lazuli is also mined in Chile. Small quantities are also produces in Siberia, in Colorado in the United States, and in Myanmar. Lapiz lazuli is ranked 5 to 6 on the Mohs Scale of Hardness and is somewhat porous and should be protected from harsh chemicals. Lapis is not very hard, and should be protected from other jewelry when store to avoid scratches. Lapis lazuli is the anniversary gemstone representing the 9th year of marriage.

Nephrite

Asian artisans have used nephrite for thousands of years tot produce intricate carved objects and jewelry. Nephrite is one of two different mineral types more commonly known as a form of Jade. Nephrite is made of calcium, sodium, magnesium, aluminum, and iron. The dark green variety of nephrite is sometimes known as "spinach jade" and is usually opaque to translucent. In addition to green, other colors of this gem are yellow, red, brown, white, gray and black. New Zealand and China are principal sources of nephrite as well as Australia, Brazil, Canada and in Alaska and Wyoming in the United States. Nephrite is most often available in a cabochon cut or as beads, and is ranked 6 to 6.5 on the Mohs Scale of Hardness. Store your nephrite jewelry separately, avoid the use of ultrasonic cleaners and do not expose to extreme temperatures.

Onyx

The name of this gemstone comes from the Greek word onyx, which means fingernail. According to Roman mythology, cupid cut the divine fingernails of Venus with an arrowhead while she was sleeping. The fates turned the clippings into stone so that no part of the goddess would ever perish. Sometimes the onyx has a white band or ribbons that are often carved into delicate raised designs with layered backgrounds called cameos. The onyx used in our jewelry is formed by color enhancing Chalcedony, which is a variety of quartz. The primary color used in our line is black, although blue and other colors are sometimes used to accent a particular design. It is mined in Brazil, Uruguay and California. Onyx ranks 6.5 to 7 on the Mohs Scale of Hardness, and is the anniversary gemstone representing the 7th year of marriage.

Opal

Opals were formed millions of years ago when water and silica flowed into cracks of the earth and hardened. Fire Opals are gems with a transparent to translucent color of yellow, orange or red that is a uniform color throughout the stone. Other types of opals are typically white and are prized for their unique play of rainbow colors. The most valued variety is the black opal. Today's supplies of opal come primarily from Australia, Mexico and the United State. Most opals are not faceted but cut into rounded or free-form cabochons. Although opal is rarely enhanced by methods other than cutting and polishing, opals can be treated to enhance their color. Opals can also be permeated with colorless oil, wax, resin, plastic, and hardeners to improve their appearance and durability. Opal with or without enhancement, should be treated with some care. It is softer than many other gemstones and should be stored carefully to avoid being scratched by other jewelry. Opal contains water so it should not be exposed to long periods of intense sunshine or heat. Opal is ranked 5.5 to 6.5 on the Mohs Scale of Hardness. Opal, along with tourmaline, is the birthstone for October and is the anniversary gemstone representing the 14th year of marriage.

Peridot

Peridot is one of the few gemstones which exist only in the color of green. The ancient romans noticed its color did not change in artificial light, so they named the stone “evening emerald”. The fresh lime green of peridot is its distinctive signature. Currently it is found in the U.S. in Arizona and New Mexico, Burma, Pakistan and China. It ranks 6.5 to 7 on the Mohs Scale of Hardness. Peridot is the traditional birthstone for the month of August, and the anniversary gemstone representing the 1st and 16th year of marriage.

Lab Ruby

Celebrated in the Bible and in ancient Sanskrit writings as the most precious of all gemstones, rubies have been the prized possession of emperors and kings throughout the ages. ruby’s inner fire has been the inspiration for innumerable legends and myths, and to this day, no red gemstone can compare to its fiery, rich hues. many people associate its brilliant crimson colors with passion and love. Ruby is the red variety of the corundum mineral species. Rubies can only be red, but are offered in various shades such as pink-red, purple-red or a brown-red. It ranks 9 on the Mohs Scale of Hardness. The ruby is the traditional birthstone for the month of July, and the anniversary gemstone representing the 15th and 40th year of marriage. Learn more about lab gemstones.

Lab Sapphire

Sapphire, beloved for centuries, is most often referred to as the ultimate blue gemstone, and comes from the mineral corundum. The ancient Persian rulers believed that the earth rested on a giant sapphire and its reflection colored the heavens blue. A gift of a sapphire symbolizes a pledge of trust and loyalty. Sapphire is one of the most durable of gemstones and they come in several colors including pink, white, and orange, but are most noted for their rich blue color. It ranks 9 on the Mohs Scale of Hardness. The blue sapphire is the traditional birthstone for the month of September, and the anniversary gemstone representing the 5th and 45th year of marriage. The white sapphire is the modern birthstone for the month of April. Learn more about lab gemstones.

Smokey Quartz

Smokey quartz gets its color as a result of natural radiation. It is known for its versatility, which is alluring in color and clarity. Sources include Brazil, Switzerland, the Himalayas, and Mexico. Smokey Quartz is ranked 7 on the Mohs Scale of Hardness. ultrasonic cleaners are generally safe but should be used with caution, steaming is not recommended. Avoid prolonged exposure to excessive heat which can alter the color or damage the stone.

Tourmaline

For centuries tourmalines have adorned the jewels of royalty. The empress Dowager Tz’u Hsi, the last empress of China, valued the rich pink colors above all other gemstones. The people of ancient Ceylon called tourmaline “turmali,” the Sinhalese word for “more colors.” Perhaps this is why ancient mystics believed tourmaline could encourage artistic intuition. Because tourmalines are a complex crystal often mixed with elements such as aluminum and boron, it occurs in more colors than most minerals, and can even have more than one color or hue. Green and red are the better known colors as well as multicolored stones. Dark blue, blue-green, and green tourmalines are occasionally heated to lighten their color. Red tourmalines, also known as rubellites, and pink varieties are sometimes heated or irradiated to improve their colors. Heat and irradiation color enhancement of tourmalines is permanent. Tourmalines are mined around the world, and in Maine and Utah in the U.S. It ranks 7 to 7.5 on the Mohs Scale of Hardness. Tourmaline is an alternative to the opal as the modern birthstone for October, and the anniversary gemstone representing the 5th and 8th year of marriage.

Turquoise

Turquoise is among the oldest known gemstones - it has been mined since 3,200 BC. It graced these necks of Egyptian Pharoahs and adorned the ceremonial dress of early Native Americans. Turquoise is an opaque, light to dark blue or blue-green gem. The finest color is an intense blue. Turquoise may contain narrow veins of other materials either isolated or as a network. They are usually black, brown, or yellowish-brown in color. Known as the matrix, these veins of color are sometimes in the form of an intricate pattern, called a spider web. To improve its color and durability, turquoise is commonly permeated with plastic, a stable enhancement. It is also sometimes permeated with colorless oil, or wax, which is considered not as stable as plastic. Some turquoise is dyed to improve its color, but rarely, as this is an unstable enhancement. Turquoise ranks 5 to 6 on the Mohs Scale of Hardness and special care is required regardless of whether or not it is enhanced. A porous gemstone, turquoise can absorb anything it touches. Avoid contact with cosmetics, perfumes, skin oil, and other chemicals. Do not expose to extreme temperatures. Turquoise is the birthstone for December along with Zircon and Tanzanite, and the anniversary gemstone representing the 11th year of marriage.

Zircon

In the middle ages, zircon was said to aid sleep, bring prosperity, and promote honor and wisdom to those who wear it. The name probably comes from the Persian word zargun which means “gold-colored.” The mineral zircon comes in many colors using a heat enhancement process. It is most often sought after in the shade of blue, and is famous for its luster and fire. Major sources of zircon are found in Thailand, Cambodia, and Vietnam. It ranks 7.5 on the Mohs Scale of Hardness. Zircon is the modern birthstone for the month of December, and the anniversary gemstone representing the 4th year of marriage.

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Mohs Scale of Hardness

The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. It was created in 1812 by the German geologist and mineralogist Friedrich Mohs and is one of several definitions of hardness in materials science.

Mohs Scale of Hardness
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Lab Gemstones

The first lab gemstone was produced in 1902 in Paris, France by a chemist named Louis Verneuil. A gemstone that is grown in a laboratory is not imitation or artificial, and is carefully crystallized over time. It has essentially the same optical, physical and chemical properties as a natural gemstone. Only a trained gemologist can tell them apart.

Natural gemstones are crystals formed by heat and pressure within the earth. A similar heat and pressure environment is created in the laboratory using the same natural elements. This process takes 10 to 14 months to complete.