Guide to Gemstones

 

Alexandrite

Alexandrite was discovered in Russia’s Ural Mountains in 1830 and takes its name from Tsar Alexander II. Alexandrite displays a fascinating phenomena: it appears green in the daylight but red in candlelight. Incidentally, these were the colors of Russia’s royal family, and this coincidence further cements the gem’s connection to Tsarist Russia. High quality alexandrite is one of the world’s rarest and most expensive gems. Along with moonstone and pearl, Alexandrite is one of the birthstones for June and also is the gem for the 55th wedding anniversary.

“Certified Strong Change Alexandrite 26.75cts” by David Weinberg / CC BY-SA 3.0

Certified Strong Change Alexandrite 26.75cts” by David Weinberg / CC BY-SA 3.0



Color: Alexandrite is green in daylight or fluorescent light but red in incandescent light. Though these colors tend to be muted, fine alexandrite makes a remarkable shift from bluish green to “raspberry red.”

Clarity: Often lightly included. Minor clarity characteristics are accepted and generally expected.

Cut: Usually faceted in traditional shapes and styles. Attention has to be paid so that the cut maximizes the visibility of the color change.

Carat Weight: Extremely rare over 5 carats, especially in high quality.

Care: Alexandrite generally possess excellent wearability.

Hardness: High scratch resistance. Alexandrite rates 8.5 on the Mohs Hardness Scale.

Gemology: Alexandrite is a variety of the mineral species chrysoberyl. Primarily composed of beryllium, aluminum, and oxygen, Alexandrite’s color comes from trace amounts of chromium, which also colors emeralds and rubies.  

Geology: Alexandrite generally forms in pegmatites, areas in the earth’s crust where gems crystallize from metal rock and hot chemical rich fluids.

Sources: Brazil, Sri Lanka, India, Madagascar, and Tanzania. Russia was the primary source until the early 20th century.


Birthstone: June

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Amethyst

Amethyst’s name comes from the Greek word amethystos, which translates to “not drunken.” For centuries, people believed that wine drunk from an amethyst cup would not cause intoxication. In Roman mythology, the goddess Diana turned a maiden named Amethyst into stone to save her from being eaten alive by tigers, and the god Bacchus poured wine over the stone and stained it purple. According to folklore, Amethyst will bring success in competition whether sport or business. Amethyst frequently appears in royal jewels, both in antiquity and modern times. Amethyst is the birthstone for February and the zodiac sign Pisces and is also the gem for the 6th wedding anniversary.

“Amethyst, Magaliesburg, South Africa” by JJ Harrison / CC BY-SA 3.0

Amethyst, Magaliesburg, South Africa” by JJ Harrison / CC BY-SA 3.0



Color: Light to dark purple. Deep “royal” purple is the most expensive.

Clarity: Often lightly included. Minor clarity characteristics are accepted.

Cut: Faceted in many shapes and styles. Also cabochons, carvings, fantasy cuts, and beads.

Carat Weight: Available in weights up to 50 carats or more. There are faceted amethysts at weigh over 1,000 carats.


Care: Amethyst have good wearability, but may fade if exposed to intense light for extended periods.

Hardness: Moderated scratch resistance. Amethysts rate 7 on the Mohs Hardness Scale.

Gemology: Amethyst is a variety of quartz, the most abundant mineral in the Earth’s crust, and is composed almost entirely of silicon and oxygen with its color coming from trace amounts of iron.

Geology: Often forms in cavities and crevices that exist within larger rock formations.

Sources: Brazil Uruguay, Namibia, Tanzania, and Zambia.


Birthstone: February, Pisces

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Aquamarine

Aquamarine’s name comes from the Latin aqua marina, which translates to “sea water.” In the ancient world, aquamarine was the spirit of the sea, and legends state that this gem is the treasure of mermaids. During the Middle Ages, Europeans held that this gem grant its wearer wisdom, protection from evil, and the ability to divine the future. In other areas, aquamarine was imbued with the ability to create harmonious marriages. Aquamarine is the birthstone for March and the gem for the 19th wedding anniversary.

“5 Brazilian Aquamarine” by Mauro Cateb / CC BY-SA 3.0

5 Brazilian Aquamarine” by Mauro Cateb / CC BY-SA 3.0

Color: Usually light blue-green to greenish blue. Bright, pure clue is the most expensive.

Clarity: Often almost inclusion-free.

 

Cut: Faceted in may shapes and styles, including cabochons, carvings, fantasy cuts, and beads.

Carat Weight: Available in wide range and up to 50 carats or more.

Care: Aquamarine generally has very good wearability.

Hardness: Moderate to high scratch resistance. Aquamarine rates 7.5 to 8 on the Mohs Hardness Scale.

Gemology: A variety of the mineral species beryl as is emerald. Aquamarine is primarily composed of beryllium, aluminum, silicon, and oxygen. The color comes from trace amounts of iron.

Geology: Aquamarine generally forms in pegmatites, areas in the earth’s crust where gems crystallize from metal rock and hot chemical rich fluids.

Sources: Brazil, Mozambique, Nigeria, and Zambia.


Birthstone: March

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Citrine

Citrine takes its name from the Latin citrus meaning citron, a citrus fruit related to lemons, limes, oranges, and grapefruits. Folklore holds that citrine will protect its wearer from evil thoughts. Citrine is the birthstone for November along with Topaz and is also the gem for the 13th wedding anniversary.

“Citrine Cut” by Wela49~commonswiki / CC BY-SA 3.0

Citrine Cut” by Wela49~commonswiki / CC BY-SA 3.0

Color: Light yellow to dark orange. Deep, rich “Maderina” orange is the most expensive.

Clarity: Often almost inclusion-free.

Cut: Faced in many shapes and styles including cabochons, carvings, fantasy cuts, and beads.

Carat Weight: Available in a wide range of sizes, up to 50 carats or more.

Care: Citrine has generally good wearability.

Hardness: Moderate scratch resistance. Citrine rates 7 on the Mohs Hardness Scale.

Gemology: Citrine is a variety of quartz, the most abundant mineral in the Earth’s crust, and is composed almost entirely of silicon and oxygen with its color coming from trace amounts of iron.

Geology: Often forms in cavities and crevices that exist within larger rock formations.

Sources: Brazil, Bolivia, India, Madagascar, Myanmar, Russia, and Sri Lanka.


Birthstone: November

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Diamond

Diamond takes its name from the Greek amadas, which translates to unconquerable. For centuries, it was assumed that diamonds were unbreakable and that they could grant their owner strength, courage, success, and enduring love. Diamonds most likely arrived in Europe during the Roman Empire, but the gemstone had already been prized in India for centuries. Diamonds have been associated with courtship and love for over 500 years. In 1477, Archduke Maximilian of Austria gave Mary of Burgundy a diamond ring as a symbol of his love and fidelity. Today, over 80% of American brides receive a diamond engagement ring. Diamond is the birthstone for April and is the gem for the 10th, 60th, and 75th wedding anniversaries.

Diamond Stock Image

Color: The normal market range is colorless to light yellow, brown or gray. Deeper yellows, browns, and grays, as well as all shades of all other hues, are classified as fancy colors. In the normal range, colorless diamonds command the highest price. In the fancy range, the value increases with the intensity of the color. Vivid reds, pinks, purples, greens, and blues are exceedingly rare and command astonishing prices.  

Clarity: Standards are stricter than for any other gem. Graded on a detailed sale that runs from flawless under 10x magnification to obviously included to the untrained eye.

Cut: Faceted in many shapes and styles. The round brilliant cut is the most popular.  

Carat Weight: Available in all sizes. .5 carats to 1 carat is the average range.

Care: Diamond has good to excellent wearability.

Hardness: Exceptional scratch resistance. Diamonds rate 10 on the Mohs Hardness Scale.

Gemology: Diamonds are classified as a mineral species and are composed almost completely of pure carbon.

Geology: Most diamonds formed around 100 miles below Earth’s surface, and the youngest are almost 1 billion years old.

Sources: Botswana, Angola, Australia, Canada, Democratic Republic of the Congo, Namibia, Russia, and South Africa.


Birthstone: April

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Emerald

Emerald’s name comes from the Greek word smaragdos, which was used to refer to most green gems. Emerald’s deep, lush green color represented fertility and life to ancient Egyptians, and ancient Romans dedicated this gem to Venus, the Roman goddess of love. The emerald has been associated with faith, harmony, and peace. Legend holds that placing an emerald under your tongue will allow you to see the future, and that wearing emeralds will bring riches and power, strengthen memory and intelligence. Emerald is the birthstone for the month of May and the astrological sign Cancer, and emeralds are the gem for the 20th and 35th wedding anniversaries. In fine quality, emeralds are among the world’s rarest and costliest gems.

“5 Emeralds from Columbia” by Mauro Cateb / CC BY-SA 3.0

“5 Emeralds from Columbia” by Mauro Cateb / CC BY-SA 3.0

Color: Light to dark green, often with a slight blueish tint. Deep and vibrant bluish green emeralds are the most expensive.

Clarity: Often visibly included. Unless clarity characteristics are unsightly or threatening, they are generally considered acceptable.

Cut: The step-cut commonly referred to as the emerald cut is generally prefered for the emerald as it saves crystal weight and clearly shows the color. Emeralds are occasionally faceted in other shapes and styles, or cabochon cut.

Carat Weight: Generally available in all jewelry sizes (up to 15 or 20 carats). Fine quality emeralds greater than 10 carats are rare.

Care: Emeralds generally require gentle wear and care. Protective settings are recommended.

Hardness: Moderate to high scratch resistance. Emeralds rate 7.5 to 8 on the Mohs Hardness Scale.

Gemology: Emeralds are a gem variety of the mineral beryl as are Aquamarine gems. In order for a gem quality beryl to qualify as an emerald, the color must be reasonably intense green. Pale and yellowish gems are classified as green beryl instead of emerald. Emeralds are primarily composed of beryllium, aluminum, silicon, and oxygen.

Geology: Emeralds form in hydrothermal veins, where super hot mixtures of water and chemical ingredients flow through cracks in existing rocks and solidify into seams that range from a few inches to several feet.  

Sources: Colombia, Brazil, Zambia, Afghanistan. North Carolina receives an honorable mention as a minor source of emerald production!


Birthstone: May, Cancer

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Garnet

Garnet takes its name from either the French grenat, which translates to “red like a pomegranate,” or the Latin granatus, which translates to “grain-like” and may refer to the appearance of small garnet crystals. Ancient Egyptians prized garnet over 5,000 years ago, but, in the ancient world, garnet was limited to shades of red. Garnet traditionally symbolizes faith, truth, friendship, and loyalty. For many centuries, people believed that the gem could dispel fear, pacify discord, protect travelers, and inspire intimacy. All colors of garnet are the birthstone for January and the zodiac sign Aquarius. Garnet is the gemstone for the 2nd wedding anniversary.

Garnet Public Domain



Color: Many colors and intensities of red, purple, pink, orange, yellow, and green.

Clarity: Often lightly included, and minor clarity characteristics are accepted.

Cut: Faceted into a wide variety of shapes and styles, including cabochons, fantasy cuts, and beads.

Carat Weight: Normally available up to 15 or 20 carats.

Care: Generally good wearability.

Hardness: Moderate scratch resistance. Garnet rates 6.5 to 7.5 on the Moh’s Hardness Scale.

Gemology: Garnets are a group of related minerals that share a common crystal structure and vary slightly in chemical composition. The most important garnet species include almandite, malaya, rhodolite, spessartite, and tsavorite.

Geology: Garnets form through contact metamorphism, which occurs when magma is forced into existing geologic formations.

 

Sources: Australia, Brazil, China, India, Kenya, Madagascar, Namibia, Nigeria, Russia, Sri Lanka , Tanzania, and Zambia.

Birthstone: January, Aquarius

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Jade- Jadeite

The Chinese word for jade traditionally applies to any carvable gem, and, today, both jadeite and nephrite are considered jade. Jadeite arrived in China in the late 18th century and quickly became highly valued and sought after, and, in finest quality, jadeite is among the most expensive and rarest gems. Both the words jade and jadeite come from the Spanish piedra de ijada, which translates to “stone of the loins,” which relates to indigenous belief in South America that jade could prevent and cure kidney illnesses. The Maya and other pre-Columbian cultures valued jadeite for centuries before the gem became synonymous with China. Both jadeite and nephrite are gems for the 12th wedding anniversary.

“Chinese Jadeite Buttons” by Gregory Phillips /  CC-BY-SA 3.0

“Chinese Jadeite Buttons” by Gregory Phillips /  CC-BY-SA 3.0

Color: Various shades of green, lavender, yellow, orange, and brown. Also occurs in white, gray, and black. Mixtures and markings may be prized, for instance, “moss-in-snow” jade has green veins running through a white background. Pure “imperial” jade is the most expensive and sought after color of jadeite.

Clarity: Translucent to opaque but may also appear transparent.

Cut: Cabochons, carvings, and beads.

Size/Weight: Most colors are available in all sizes and occur in pieces large enough for ornamental purposes. Imperial jade is very rare even in very small sizes.

Care: Generally good wearability.

Hardness: Moderate scratch resistance. Jadeite rates 6.5 to 7 on the Mohs Hardness Scale. However, jadeite has remarkable resistance to chipping and breaking. Jadeite is considered to be the second toughest gem, behind nephrite jade.

Gemology: Classified as a mineral species, but jadeite used in gems is generally rock containing a majority jadeite with small percentages of other minerals. Jadeite is composed of sodium, aluminum, silicon, and oxygen, and jadeite takes its color from trace amounts of iron. Imperial jade’s color comes from chromium, which also is responsible for coloring ruby and emerald.

Geology: Forms when chemical rich liquid rises from deep inside the earth and fills crevices in existing rock formations.

Sources: Myanmar is currently the only major producer of gem quality jadeite, but, the pre-Columbian source, Guatemala, still has minor output.


Birthstone: N/A


 

 

Jade- Nephrite

 

Nephrite jade has been used as a gem and for functional purposes by many cultures since prehistoric times. In China, nephrite jade is a traditional symbol of prosperity and good fortune. Carved designs frequently bear symbolic meanings. For instance, bats symbolize happiness; butterflies symbolize long life; and peaches symbolize immortality. Nephrite has been used in China for over 7,000 years, well over 6,700 years longer than jadeite jade. However, nephrite is very inexpensive compared to jadeite. Both nephrite and jadeite are the gem for the 12th wedding anniversary.

 

Nephrite Jade

 

Public Domain

 

Color: Light to dark green, yellow, and brown. Also occurs in white, gray, and black.

Clarity: Translucent to opaque.

Cut: Cabochons, carvings, and beads.

Size/Weight: All sizes are available, up to very large pieces for ornamental purposes.

Care: Nephrite jade generally has very good wearability.

Hardness: Moderate scratch resistance. Nephrite rates 6 to 6.5 on the Mohs Hardness Scale. However, Nephrite has remarkable resistance to chipping and breaking. Nephrite is considered to be the toughest gem.

Gemology: Nephrite is a rock-like gem material with a variable composition and is generally composed of calcium, hydrogen, iron, magnesium, oxygen, and silicon. Nephrite’s color comes from its iron content.

Geology: Nephrite forms from regional metamorphism, such as mountain building events.

Sources: Canada, United States, Australia, New Zealand, China, Russia, Taiwan.

Birthstone: N/A


 

Lapis Lazuli

Lapis Lazuli takes its name from Latin and Arabic words that translate to “heaven-blue stone,” and the gem is colloquially referred to as Lapis. Lapis Lazuli has been prized for millennia, and researchers have found lapis lazuli jewelry that is over 4,000 years old. The gem is often taken as a symbol of truth and purity, and people have traditionally believed that lapis lazuli can summon angels, alleviate depression, and protect its wearer from evil. Lapis Lazuli is the gem for the 9th wedding anniversary.

“A sample from the Sar-i Sang mine in Afghanistan, where lapis lazuli has been mined since the 7th Millennium BC.” by Didier Descouens / CC BY-SA 4.0

A sample from the Sar-i Sang mine in Afghanistan, where lapis lazuli has been mined since the 7th Millennium BC.” by Didier Descouens / CC BY-SA 4.0

Color: Medium to dark blue. Deep violet “midnight” blue is the most expensive.

Clarity: Always opaque.

Cut: Cabochons, carvings, tablets, and beads.

Size/Weight: All sizes available. Lapis Lazuli occurs in sizes sizeable enough to bear large carvings and to serve ornamental purposes.

Care: Lapis Lazuli generally has fair wearability.

Hardness: Moderate scratch resistance. Lapis Lazuli rates 5 to 6 on the Mohs Hardness Scale.

Gemology: Lapis Lazuli is technically classified as a rock due because of its mixed mineral composition. Color is caused by sulphur content.

Geology: Lapis Lazuli forms from regional metamorphism, such as mountain building events.

Sources: Afghanistan has been the main source of Lapis Lazuli for over 6,000 years. Chile, Myanmar, Russia, Tajikistan, and the United States are other sources.


Birthstone: N/A

 


 

Moonstone

According to ancient Indian tradition, moonstones are crystallized moonbeams. Legend has it that if you hold a moonstone in our mouth under the light of the full moon, you will be able to see your future. Along with alexandrite and pearl, moonstone is one of the birthstones for June.

“Moonstone from Africa” by Matthew Hardy / CC BY-SA 3.0

Moonstone from Africa” by Matthew Hardy / CC BY-SA 3.0

Phenomenon: Moonstone displays adularescence, which is a glow that appears to float inside of the gem. In fine quality, it is soft yet bright.  

Color: Typically colorless, white, or gray, but light yellow, orange, and brown moonstones are available. Colorless with sky-blue adularescence is the most expensive.

Clarity: Usually translucent to opaque, but sometimes nearly transparent.

Cut: Cabochons, carvings, and beads. Long narrow cabochons have a cat’s eye appearance.

Carat Weight: Normally available in all jewelry sizes, up to 15 to 20 carats.

Care: Moonstone requires gentle wear and care, protective settings are recommended for moonstone-bearing jewelry.

Hardness: Moderate scratch resistance. Moonstone rates 6 to 6.5 on the Mohs Hardness Scale.

Gemology: Moonstone is a variety of labradorite feldspar. Feldspars make up nearly half of the Earth’s crust. Moonstone is primarily composed of potassium, aluminum, silicon, and oxygen.

Geology: Moonstone typically forms in pegmatites, areas in the earth’s crust where gems crystallize from metal rock and hot chemical rich fluids.


Birthstone: June

 


 

Morganite

Morganite was discovered in California and Madagascar in the early 20th century and takes its name from legendary financier and gem enthusiast J.P. Morgan. Morganite is one of the rarer varieties of the mineral variety Beryl, which includes both emerald and aquamarine.

“Morganite” by Rob Lavinski / CC BY-SA 3.0

Morganite” by Rob Lavinski / CC BY-SA 3.0

Color: Various shades of pink ranging from soft pink, to orangish pink to purplish pink. Strong pink to magenta colored morganites are the most prizes.

Clarity: Morganite it typically inclusion-free in smaller sizes, but larger gems may have visible inclusions.

Cut: Morganite is faceted into traditional shapes, as well as cabochons, beads, and fantasy cuts.

Carat Weight: Morganite is available in a wide variety of sizes, and larger gems are not uncommon.

Care: Morganite has generally very good wearability.

Hardness: Morganite has moderate to high scratch resistance and rates 7.5 to 8 on the Mohs Hardness Scale.

Gemology: A variety of the mineral species beryl as are emerald and aquamarine. Morganite is primarily composed of beryllium, aluminum, silicon, and oxygen. The color comes from trace amounts of iron.

Geology: Morganite generally forms in pegmatites, areas in the earth’s crust where gems crystallize from metal rock and hot chemical rich fluids.

Sources: Madagascar and the United States.


Birthstone: N/A


 

Onyx

Onyx’s name is Greek and literally translates to claw. Greek mythology holds that Cupid cut the goddess Venus’s fingernails while she slept, and the fates transformed the clippings into onyx, so that no part of the goddess would become mortal. In Indian lore, onyx soothes passions and calms the heart. New Age gm therapists believe that the gem is useful for fostering strength and discipline. Onyx experienced a surge of popularity during the Art Deco period, approximately 1910 to 1935. Onyx’s color ensures that it is always in vogue and is popular with men. Onyx is the birthstone for the astrological sign Leo and is the gem of the 7th wedding anniversary.

“Onyx” by Simon Eugster / CC BY-SA 3.0

Onyx” by Simon Eugster / CC BY-SA 3.0

Color: Black onyx is solid in color. Other types of onyx feature straight contrasting bands. Black and white combinations are still classified as onyx. Brown alternating with black or white is classified as sardonyx.

Clarity: Totally opaque.

Cut: Cabochons, carvings, tablets, and beads.

Size/Weight: All sizes available from jewelry to larger ornamental sizes.  

Care: Generally good wearability.

Hardness: Moderate scratch resistance. Onyx rates 6.5 to 7 on the Mohs Hardness Scale.

Gemology: Onyx is a variety of the mineral species chalcedony and is composed of silicon and oxygen. “California onyx” and “Mexican onyx” are not true onyx. They are calcite variations and bear no relation to true onyx.

Geology: Onyx forms in cavities and crevices within larger rocker formations because of melted rock material and/or chemical rich fluid.


Birthstone: Leo

 


 

Opal

Opal takes its name from the Sanskrit upala, which translates to gem or jewel. Westerners have valued opal since the days of the Roman Empire, but 6000 year old opal artifacts have been found in Kenya. For millennia people have considered opal to be among the most enchanting and magical of the gems because of its ability to show the colors of all other gems. In Europe, opal is a symbol of purity and hope, and in Middle Eastern legend opal’s colors come from lightning. Despite what Sir Walter Scott wrote in Anne of Gerstein, opals are not unlucky, and the gem is one of the birthstones for October and the gem for the 14th wedding anniversary.

“Opal Australia” by Hannes Grobe / CC BY-SA 2.5

Opal Australia” by Hannes Grobe / CC BY-SA 2.5



Color: Opal displays a play-of-color, dancing flashes of rainbow hues. In fine quality, the colors form an attractive pattern and are bright. The gem’s full color range includes white, gray, black, red, orange, yellow, brown, and blue.

Clarity: Most typically opaque or translucent. Rarely transparent.

Cut: Cabochons are most common, but fire opal is frequently faceted. Carvings and beads are also popular.  

Carat Weight: Available up to 15 or 20 carats.

Care: Opal requires gentle wear and care. Protective settings are recommended for opal.

Hardness: Moderate scratch resistance. Opal rates 5 to 6.5 on the Mohs Hardness Scale.

Gemology: Opal is considered a mineral species and is generally composed of silicon and oxygen.

Geology: Opal forms during sedimentary processes and solidifies at a rade of 1 inch every 20 million years.

Sources: Australia, Brazil, Mexico.


Birthstone: October

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Pearl

Pearls have been prized since the start of human culture, and, in the ancient world, pearls were widely considered to be the most valuable of all material things. Asian folklore holds that pearls were drops of divine moisture from dragons in the sky. Pearls are frequently linked to the moon and water. Due to this correspondence, pearls frequently symbolize love and purity. Alongside alexandrite and moonstone, pearls are one of the birthstones for June. Due to pearl’s unique formation process, appearance, and use in jewelry there are a completely different set of criteria for evaluation of pearl’s value.

“Variety of Pearls in an Oyster Clam” by Hannes Grobe /  CC BY-SA 3.0

Variety of Pearls in an Oyster Clam” by Hannes Grobe /  CC BY-SA 3.0  

Natural vs. Cultured: Around two dozen varieties of mollusks naturally produce pearls. However, almost all pearls available on the market today result from human efforts. Pearls produced because of human assistance are considered cultured.

Pearl Types

Akoya: Akoya pearls come from the coasts of Japan and China and typically range from 4 to 8 millimeters. round s and near rounds are common. Akoya pearls are typically white or cream colored but can also be pink, yellow, blue, and gray. Akoya pearls can have a near mirror quality luster and frequently have pink or green overtones. These are the most popular pearls on the market.

South Sea: South Sea pearls are the rarest and most expensive pearls and originate in Australia, Indonesia, and the Philippines. South Sea pearls can grow to 8 to 18 millimeters and can be white, cream, silver gray, golden yellow, rosé pink, or peacock blue, with either rosé, green, or blue overtones. Luster is satiny instead of glossy. These pearls are frequently “circled” in shape with parallel ridges.

Tahitian: These striking pearls come from French Polynesia. New Zealand is another source. These pearls can be as large as South Sea pearls, frequently have “circled” shapes, and feature metallic luster. Tahitian pearls can be silver gray, golden yellow, bronze, copper, cherry red, pistachio, or aubergine colored with striking overtones.  

Freshwater: Freshwater pearls are the most affordable pearls and come in a wide variety of sizes, shapes, and colors. Streams, rivers, lakes in China, Japan, and the United States are the source for these pearls.

Value Factors and Other Information

Size: Pearl’s size is measured in millimeters and depends on type. Fine pearls near the top of their size range are prized.

Shape: Shape is frequently broken down into three categories: spherical, symmetrical, and baroque. Spherical pearls are round or near round. Symmetrical pearls are ovular, button-shaped, drop shaped, etc. Baroque pearls are irregularly shaped. Spherical pearls command the highest price.

Color: Though commonly thought of as white or cream colored, pearls can assume a wide range of colors. In addition to basic body color, the blush-like overtones and the iridescent orient effect are considered components of color.

Luster: Luster refers to the sharpness of light reflections from pearl’s surface. Different varieties of pearl have different potential lusters, but luster is considered a critical component of pearl’s aesthetic value and pricing.

Surface: Freedom from blemishes including bumps, spots, and scratches is valued. Though these characteristics are unavoidable, the lesser their extent the greater value of the pearl.

Nacre: Nacre is the thickness of the pearl’s coating. Pearl’s long-lasting beauty and value are dependent upon this factor.

Matching: Similarity in color, size, luster, etc are important for pearls that are incorporated into necklaces.  

Gemology: Along with amber, coral, and shell, pearls are considered an organic gem.

Care: Pearls require gentle wear and care. For more information, check out Protecting Your Priceless Pearls: One Dozen Tips and Tricks.

Hardness: Low scratch resistance. Pearls rate 2.5 to 4 on the Mohs Hardness Scale.


Birthstone: June 

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Peridot

Peridot’s name comes from the Arabic word faridat, which translates to gem. Ancient Egyptians called peridot the “gem of the sun” and believed that peridot could attract wealth and repel evil spirits. Peridot is the birthstone for August and the zodiac sign Libra and is the gem for the 16th wedding anniversary.

“Facettierter Peridot, Varietät der Olivingruppe aus China” by Don Guennie / CC BY-SA 4.0Facettierter Peridot, Varietät der Olivingruppe aus China” by Don Guennie / CC BY-SA 4.0

Color: Peridot ranges in color from light to dark greenish yellow or yellowish green and is frequently a pale “olive” but can be a bright “golden lime” color.  

Clarity: Often lightly included. Minor clarity characteristics are accepted.

Cut: Faced in many shapes and styles, but also made into cabochons, fantasy cuts, and beads.

Carat Weight: Normally available in all jewelry sizes, up to 15 or 20 carats.

Care: Even though Peridot has generally good wearability, protective settings are recommended for peridot bearing jewelry.  

Hardness: Peridot has moderate scratch resistance and rates 6.5 to 7 on the Mohs Hardness Scale.

Gemology: Peridot is a mineral variety of the mineral group olivine and is typically composed of magnesium, iron, silicon, and oxygen.

Geology: Peridot forms during the crystallization of melted rock material in the Earth’s mantel. Extraterrestrial peridot has been found in meteorites but is extremely rare.

Sources: The San Carlos Indian Reservation in Arizona, China, Myanmar, Pakistan, Russia, Sri Lanka, and Tanzania.

Birthstone: August, Libra

 

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Rhodolite Garnet   

Rhodolite Garnet takes its name from the Greek words rhodon and lithos, which translate to rose and stone respectively. The name was give to rhododendron-red garnets that were found in the early 20th century in North Carolina. Rhodolite garnet shares the meanings and correspondences assigned to other garnets, such as truth, friendship, and faith. Folklore holds that garnets are capable of alleviating fear, calming chaos, protecting travelers, and inspiring deep affection. Along with other garnets, rhodolite garnet is the birthstone for January and Aquarius and is the gem for the 2nd wedding anniversary.

Rhodolite Garnet

Public Domain

Color: Light pink to dark purple-red. Range can be described as spanning “rose” to “raspberry.”

Clarity: Often lightly included and minor clarity characteristics are accepted.

Cut: Faceted in many shapes and styles. Cabochons, fantasy cuts, and beads are also common.

Carat: Available in a very wide range, up to 50 carats or more.    

Care: Rhodolite garnet has good wearability.

Hardness: Moderate scratch resistance. Rhodolite garnet rates 7 to 7.5 on the Mohs Hardness Scale.  

Gemology: Rhodolite garnet is a garnet variety and is predominately a mixture of almandite and pyrope species. Rhodolite garnet is generally composed of aluminum, iron, magnesium, oxygen, and silicon.


Geology: Rhodolite garnet forms through contact metamorphism, when melted rock material and/or chemical rich fluids enter existing geologic formations.

Sources: Kenya, Madagascar, Sri Lanka, Tanzania, and Zimbabwe


Birthstone: January, Aquarius

 


 

Ruby

Ruby takes its name from the Latin ruber, which translates to red, and throughout the gem’s illustrious history people have believed an unquenchable fire burns at the stone’s center. Ruby has long been regarded as one of the most precious gems. In ancient India, the Sanskrit name for ruby, ratnaraj, translates to “Gem King,” and ancient Indian folklore holds that rubies can preserve physical and mental health, prevent evil thoughts, mollify disputes, and ensure safety. In Medieval Europe, ruby was regarded as the “lord of all stones,” and Europeans believed that the stone would bestow perfect peace and happiness on its wearer. Ruby is the birthstone for July and the zodiac sign Capricorn and is the gem for the 15th and 40th wedding anniversary.  

“Cut Ruby Gemstone with Inclusions” by Humanfeather / CC BY-SA 3.0

Cut Ruby Gemstone with Inclusions” by Humanfeather / CC BY-SA 3.0

Color: Medium to dark red, with occasional orangish, purplish, or pinkish tints. Deep red rubies command the highest price.

Clarity: Often lightly included and minor clarity characteristics are accepted. “Commercial” quality rubies can be opaque or translucent and cost a fraction of the price of fine quality rubies.

Cut: Usually faceted in traditional shapes and styles, though cabochon and beads are available.  

Carat Weight: Fine quality rubies are rare at weights over 5 carats.

Care: Rubies have very good to excellent wearability.

Hardness: Very high scratch resistance. Rubies rate 9 on the Mohs Hardness Scale.

Gemology: Along with star ruby, sapphire, and star sapphire, ruby is a variety of corundum. In order for a corundum gem to meet the technical qualifications for a ruby designation, the gem must have a dominant hue of red and an overall color at least moderately dark and strong.

Geology: Rubies can form during either igneous or metamorphic processes.

Sources: For over 4 centuries, Myanmar has been the leading producer of rubies. Cambodia, Kenya, Madagascar, Tanzania, and Vietnam are other sources.


Birthstone: July, Capricorn

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Sapphire

Sapphire takes its name from the Greek word sappheiros, which originally referred to all deep blue gems. Sapphires have been tied to monarchy and nobility throughout their history. In Ancient Rome, nobility wore sapphires to guard against treachery and treason. The British Crown Jewels feature a sapphire that Edward the Confessor possessed in 1066, and Princess Diana received a ring set with a large blue sapphire when she became engaged to Prince Charles in 1981. In European folklore, sapphires signified truth, sincerity, and faithfulness, and wizards were said to have used the gem in order to control spirits and divine the future. Since the 12th century, clergymen have worn sapphires as symbols of heaven. Sapphire is the birthstone for September and the zodiac sign Taurus and is the gem for the 5th and 45th wedding anniversaries.

“Sapphire” by Thaneywaney / CC BY-SA 3.0

Sapphire” by Thaneywaney / CC BY-SA 3.0     

Color: Light to dark blue, and rich deep blue sapphires with a tinge of violent command the highest prices. Fancy sapphires are available in a wide variety of colors, including pink, purple, yellow, orange, and green. Prior to the 18th century, fancy color sapphires were thought to be other gems on the basis of color, but due to advancements in mineralogy and gemology during the 1700s fancy colored sapphires were finally understood to be sapphires and varieties of corundum.

Clarity: Often lightly included and minor clarity characteristics are accepted. “Commercial” quality sapphires can be opaque or translucent.

Cut: Usually faceted in traditional shapes and styles or occasionally fashioned into cabochons or beads.

Carat Weight: Available in all jewelry sizes up to 15 or 20 carats.

Care: Sapphires have very good to excellent wearability.

Hardness: Very high scratch resistance. Sapphires rate a 9 on the Mohs Hardness Scale.

Gemology: Sapphires are a variety of corundum along with ruby, star ruby, and star sapphire. In the gem trade the word sapphire alone refers to blue sapphires, and all other colors are considered fancy.  


Geology: Can form by either igneous or metamorphic process.

Sources: Madagascar and Southeastern Asian countries, including Cambodia, Laos, and Myanmar.

Birthstone: September, Taurus 

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Smoky Quartz

Smoky quartz is one of the few transparent brown gems and is the most popular choice for that color. Some consider Smoky quartz to be the national gem of Scotland, and the gem used to be referred to as cairngorm, a name coming from the country’s Cairngorm Mountains. Traditional Highland Scottish jewelry typically features smoky quartz.

Smoky Quartz

Public Domain

Color: Very light to very dark brown, verging on black.

Clarity: Often almost inclusion free.

Cut Carat Weight: Available in a wide range size, up to 50 carats or more. One of the largest, faceted gemstones is a smoky quartz that weighs 44,472 carats, which is over 19.5 lbs.

Care: Smoky quartz has generally good wearability.

Hardness: Smoky quartz has moderate scratch resistance and rates a 7 on the Mohs Hardness Scale.

Gemology: Smoky quartz is a variety of quartz, the most abundant mineral species in the earth’s crust. Other quartz varieties include amethyst, citrine, rose quartz, and tiger’s-eye. All quartz varieties are primarily composed of silicon and oxygen. Smoky quartz’s color comes from aluminum and crystal distortion.

Geology: Often forms in cavities and crevices that exist within larger rock formations.

Sources: Brazil, Mexico, and the United States.

Birthstone: N/A 

 


 

Spinel

For centuries, spinel had been confused with other gems with similar appearances, but with the advent of modern gemology in the late 18th century spinel was finally identified and recognized as an independent gem. Spinel takes its name from the Latin spina, which translates to thorn and refers to spinel’s sharp crystals. Red spinel used to be referred to as “balas ruby” in reference to the Balascia kingdom in Afghanistan, an area that is still a major spinel source. Many famous rubies are actually misidentified spinels, including the Black Prince’s Ruby, which has been a part of the British Crown Jewels for over half a millenia. Spinel is the gem for the 22nd wedding anniversary.

“Шпинель, Вьетнам” by smallru / CC BY-SA 4.0

Шпинель, Вьетнам” by smallru / CC BY-SA 4.0

Color: Shades of pink, red, and orange are the most widely available and the most popular. Spinel’s range also includes blue, violet, and purple. “Neon” pink, “ruby” red, orange-red “flame,” and “colbolt blue” are highly valued and can command a higher price.

Clarity: Often lightly included, and minor clarity characteristics are accepted.

Cut: Usually faced as round, oval, or cushion-shape brilliant cuts.

Carat Weight: Spinel is seldom found in weights over 8 or 10 carats, especially in fine quality.

Care: Spinel generally has good wearability.

Hardness: Spinel has high scratch resistance and rates 8 on the Mohs Hardness Scale.

Gemology: Spinel is classified as a mineral species and is primarily composed of magnesium, aluminum, and oxygen. A rare color-change variety of spinel exists and changes from light blue to purple during shifts from fluorescent to incandescent light.

Geology: Spinel forms through contact metamorphism, when melted rock material and/or chemical rich fluids enter existing geologic formations.

Sources: Madagascar, Myanmar, Sri Lanka, Tanzania, and Vietnam.


Birthstone: N/A

 


 

Tanzanite

Tanzanite was first identified in the early 1960s and major deposits were found within a decade. Over the past 50 years, Tanzanite has become a favorite colored gemstone. Tanzanite takes its name from Tanzania, the East African nation where it was originally discovered. Along with turquoise and zircon, tanzanite is one of the birthstones for December and was added to the birthstone list in 2002 replacing blue topaz. Tanzanite is also the gem for the 24th wedding anniversary.

“Tanazanite (Zoisite) cut stone o,38ct - C-Block Mine, Merelani Hills (Mererani), Lelatema Mts, Arusha Tanzania” by Didier Descouens / CC BY-SA 4.0

“Tanazanite (Zoisite) cut stone o,38ct - C-Block Mine, Merelani Hills (Mererani), Lelatema Mts, Arusha Tanzania” by Didier Descouens / CC BY-SA 4.0

Color: Light to dark purple, violet, or blue. Deep pure blue is the most expensive. Similarly to alexandrite and certain varieties of spinel, tanzanite may show a noticeable color shift changing from bluish to purplish when light transitions from fluorescent to incandescent.

Clarity: Often almost inclusion free.

Carat Weight: Normally available in all jewelry sizes, up to 15 or 20 carats.

Care: Tanzanite requires gentle wear and care. Protective settings are recommended for tanzanite bearing jewelry.

Hardness: Tanzanite has moderate scratch resistance and rates 6 to 7 on the Mohs Hardness Scale.

Gemology: Tanzanite is a variety of the mineral species zoisite, which commonly occurs in translucent to opaque green or pink, and rarely in transparent green. Tanzanite is composed of a complex chemical formula including calcium, aluminum, silicon, oxygen, and hydrogen.


Geology: Tanzanite formed around 600 million years ago during major geologic events in eastern Africa.

Sources: Tanzania


Birthstone: December

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Topaz

Topaz’s name comes from the Sanskrit topas meaning fire. For the ancient Egyptians, yellow topaz represented the sun god Ra and life sustaining energy. The Greeks believed that topaz imbued its wearer with strength and allowed him or her to overcome evil magic. Today, topaz is the birthstone for November and the astrological sign Sagittarius. Blue topaz is the gem for the 4th wedding anniversary and was a December birthstone until 2002 when it was replaced by Tanzanite.   

“Two Blue Topaz Crystals” by Mauro Cateb / CC BY-SA 3.0

Two Blue Topaz Crystals” by Mauro Cateb / CC BY-SA 3.0



Color: Blue, yellow, brown, orange, red, and pink. Intense reds and pinks command a higher price.

Clarity: Often almost inclusion-free.

Cut: Faceted in many shapes and styles. Sometimes carved or fantasy cut.

Carat Weight: Most colors are available in a wide variety of weights (up to 50 carats or more), but red and pink topaz are rare over 10 or 15 carats.

Care: Topaz needs gentle wear and care. Protective settings are recommended.

Hardness: High scratch resistance. Rates 8 on the Mohs Hardness Scale.

Gemology: Topaz is classified as a mineral species. Composition typically includes aluminum, fluorine, hydrogen, oxygen, and silicon.

Geology: Topaz generally forms in pegmatites, areas in the earth’s crust where gems crystallize from metal rock and hot chemical rich fluids.  

Sources: Brazil, Madagascar, Nigeria, Pakistan, and Sri Lanka.


Birthstone: November, Sagittarius

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Tourmaline

For centuries, tourmaline had been confused with other gems of similar appearance, but during the advent of modern gemology in the late 18th century tourmaline was finally identified as an independent gem. Tourmaline takes its name from the Sinhalese toramalli, which traditionally referred to mixed gems of various types. In 1900 major deposits of tourmaline were discovered in California and Maine, which has caused tourmaline to be widely regarded as an American gemstone. The last empress of China was such a tourmaline-enthusiast that she was laid to rest on a pillow of California tourmaline. Along with opal, tourmaline is one of the birthstones for October and is the gemstone for the 8th wedding anniversary.

Tourmaline Public Domain

Public Domain

Color: Tourmaline has one of the widest ranges of color out of all gemstones. Pink and green tourmalines are readily available and popular choices. Prior to the discovery of vivid blue and green tourmaline from Paraîba, Brazil in the 1990s, deep red was the most prized color of the gemstone. Tourmaline from Paraîba can command over $20,000 a carat in finest quality.

Clarity: Green tourmaline is almost inclusion free, but other colors are often lightly included and these clarity characteristics are accepted. Red and pink tourmalines are likely to have visible inclusions.

Cut: Many faceted shapes and styles are available as are cabochons, carvings, fantasy cuts, and beads.

Carat Weight: Most colors are available up to 15 or 20 carats.

Care: Tourmaline has good to fair wearability, and protective settings are recommended for tourmaline-bearing jewelry.

Hardness: Tourmaline has moderate scratch resistance and rates 7 to 7.5 on the Mohs Hardness Scale.

Gemology: Tourmaline is the name for a group of about a dozen related minerals. Most tourmaline gems come from a species known as elibaite, and tourmaline’s composition generally includes aluminum, boron, hydrogen, lithium, oxygen, silicon, and sodium, with colors coming from trace amounts of copper, chromium, iron, manganese, titanium, and vanadium.

Geology: Tourmaline generally forms in pegmatites, areas in the earth’s crust where gems crystallize from metal rock and hot chemical rich fluids.

Sources: Brazil, Afghanistan, Kenya, Madagascar, Mozambique, Namibia, Nigeria, Sri Lanka, Tanzania, and Zambia.


Birthstone: October

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Turquoise

Turquoise takes its name from the French phrase pierre turquoys, which translates to “Turkish Stone,” as Persian turquoise was once imported to Europe via Italy. Turquoise is strongly associated with the Southwestern indigenous cultures of the United States and is considered to be the most American gem of all. However, other cultural associations exist. For millennia Egyptian royalty wore turquoise and Chinese nobility prized carvings made from this gem. Ancient Persian folklore holds that turquoise guarantees prosperity, and ancient Tibetan cultures believed the gem to bring health and good luck. The Zuni of New Mexico used turquoise as an amulet against evil. Apache legends tell that turquoise lies at the end of a rainbow. Along with tanzanite and zircon, turquoise is one of the birthstones for december, and turquoise is the gem for the 11th wedding anniversary.

Persian Turquoise from Iran” by Sigma Projects / CC BY-SA 4.0

Color: Light to medium-dark greenish blue to bluish green. Bright sky-blue turquoise is the most expensive.

Clarity: Always opaque.

Cut: Cabochons, beads, carvings, inlays, and tablets.

Carat Weight: All sizes available up to sizes large enough for ornamental carvings. Not usually priced or sold by carat weight.

Care: Turquoise has generally good wearability.

Hardness: Moderate scratch resistance. Turquoise rates 5 to 6 on the Mohs Hardness Scale.

Gemology: Turquoise is classified as a mineral species and has a complex chemical formula that includes aluminum, copper, hydrogen, oxygen, phosphorous, and water.


Geology: Forms close the surface due to groundwater dissolving and redepositing masses of microscopic crystals.

Sources: Arizona, New Mexico, and Nevada.


Birthstone: December

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Zircon

Zircon may take its name from the Arabic zarkun, which translates to vermilion, or the Persian zargun, which translates to “gold colored.” Folklore holds that zircon offers protection from evil, guarantees safe travel, and brings its wealth, wisdom, and honor. Zircon is also said to assure restful sleep. Along with tanzanite and turquoise, zircon is a birthstone for December.

“Blauer Zirkon, 3.36 ct, Kambodscha, hitzebehandelt” by Don Guennie / CC BY-SA 4.0

Blauer Zirkon, 3.36 ct, Kambodscha, hitzebehandelt” by Don Guennie / CC BY-SA 4.0

Color: Blue zircon is the most popular and ranges from pastel to bright greenish blue known as “zircon blue” in the gem trade. Zircon can also be colorless, orange, yellow, brown, green, red, pink, and purple.

Clarity: Blue and colorless zircon is almost inclusion free. Other colors are often lightly included, and minor clarity characteristics are accepted.

Cut: Usually faceted in traditional shapes and styles. The zircon cut is a favorite cut for blue zircons and is the same style as the round brilliant diamond cut but with an extra row of facets around the bottom.

Carat Weight: Blue is generally available in all jewelry sizes, up to 15 or 20 carats. Other colors are rare over about 8 or 10 carats.

Care: Zircon has fair wearability and protective settings are recommended of zircon-bearing jewelry.

Hardness: Zircon has moderate scratch resistance and rates 6 to 7.5 on the Mohs Hardness Scale.

Gemology: Zircon is classified as a mineral species and is primarily composed of zirconium, silicon, and oxygen.


Geology: Zircon crystallizes from melted rock material inside the earth and is later carried toward the surface by volcanic action.

Sources: Cambodia, Myanmar, Thailand, and Vietnam.  


Birthstone: December

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The information presented in this guide comes from the Diamond Council of America’s Colored Gemstones: Compendium, 2007 edition. Malak Jewelers recommends the Diamond Council of America, the Gemological Institute of America (GIA), and the American Gem Society as excellent sources for information about gemstones, precious metals, and jewelry.