Colored Gemstones

Determining Value
Colored gemstones are among the most popular center and accent stones for jewelry items. Here, we present the basics of colored gemstones.
Gemstone 4C’s
While there are no official 4 C’s for grading colored gemstones, like there are with diamonds, many of the same principals apply. Following are the 4 C’s as they apply to colored gemstones:
Clarity
Clarity in most gemstones does not influence its value or beauty unless it breaks the surface or affects the integrity of the gemstone. In lighter colored stones, clarity may be more important than in darker stones that can mask imperfections. However, flawlessness in colored gems is even more rare than in diamonds.
The four flaws that occur in gemstones are fault, fissure, fracture and gas bubbles.
It is the type and location of a flaw that is more important than the fact that there is a flaw, since some flaws can affect the stone’s durability. Some stones are typically eye-clean such as topaz, while others are expected to have inclusions, such as emerald.
Color
Color has the greatest impact on value. The color should be pure, vibrant, even and fully saturated without being too dark or too light.
Cut
Cut affects the amount of brilliance the gemstone returns to the eye, the depth of color seen and the size of the stone. Well-cut gemstones will enhance the color of a stone, while poorly cut gemstones can turn out looking dead and lifeless.
Carat
Carat weight determines value in two ways. First, the carat weight x price per carat = total price for the stone. Second, the rarity of the size of stone compared to the normal size found will affect price.
Enhancements
Many gemstones have historically and traditionally been enhanced before bringing them to the customer. Most enhancements have been around for a very long time, some for hundreds of years or longer. The result is an improvement of nature’s beauty. It makes gems available and more affordable. Most of these enhancements are stable and no special care is required.
Gems that are not usually treated include alexandrite, black star sapphire, cat’s eye chrysoberyl, garnets, hematite, iolite, moonstone, peridot, spinel and chalcedonies such as bloodstone, fire agate, onyx and sardonyx.
Hardness vs. Toughness
Hardness describes a material’s resistance to scratching. Mineral hardness is measured using the Mohs’ scale. The higher the number, the harder the mineral is to scratch. The scale goes up incrementally from 1 until it reaches 9. The difference from 9 to 10 is greater than the difference from 1 to 9. For example, a diamond which is a 10, is 100 times harder than a sapphire or ruby which receive a 9 hardness.
Toughness refers to how easily a gemstone will chip, crack or cleave. Ratings range from poor to excellent. An emerald receives a poor toughness due to internal fractures which make emeralds prone to chipping and cracking. However, rubies and sapphires receive very good to excellent ratings.
January Birthstone: Garnet
Properties
- RI: 1.735 – 1.875
- Hardness: 7 -7.5
- Specific Gravity: 3.61 – 4.15
- Species: Garnet (Eight varieties in Group)
- Optic Character: Singly Refractive
- Phenomena: Color changed, Asterism (rare)
Major Sources
- Africa, East Africa, Sri Lanka, India, Kenya, Tanzania, Israel, Brazil, Burma, Australia, US, Russia, Madagascar, Nambia, Namibia, Nigeria, Myanmar
Enhancements
- none

Although most people think of garnet as red-brown, the versatile Garnet comes in a virtual rainbow of colors, from deep red Bohemian and Pyrope Garnet to the vibrant greens of the Russian Demantoid and African Tsavorite. The oranges and browns of Spessartite and Hessonite hail from Namibia and Sri Lanka and the subtle pinks and purples of the Rhodolite, named after the rhododendron flower, are also yours to explore.
Garnets are named after the Latin word for pomegranate because of their color and seed-like shape. The Garnet Group is composed of eight species of a diverse family of gems, all called by the name “Garnet.” No matter which color one prefers; the more vivid the color, the more valuable it is.
The birthstone of January, garnet is said to keep travelers safe, promote a long-lasting love, prevent depression, and aid hearing difficulties. Legend states that wearing a garnet can improve interpersonal relationships and keep you out of harm’s way.
February Birthstone: Amethyst
- RI: 1.544 – 1.553
- Hardness: 7
- Specific Gravity: 2.66
- Species: Quartz
- Optic Character: Double Refractive
- Phenomena: Occasionally Crystal is Bi-color (Ametrine)
- Africa, Brazil, Uruguay, Canada, US
- Heat, Irradiation – This treatment is permanent and does not need special care.

Purple passion. From refreshing lilac to ripe plum, the drama and excitement of purple are fully featured in Amethyst.
Amethyst is the birthstone for February, a purple, a very popular and affordable gemstone that ranges in color from deep purple to pale lavender. It is abundant in every corner of the Earth. It is available in small and large sizes, although as with all gemstones, very large sizes in rich, deep colors have always been rare.
Its name comes from the Greek word amethystos, meaning ‘not intoxicated’. The Greeks believed that drinking wine from amethyst cups could protect against drunkenness. Lore says that when the maiden Amethyst was turned into the crystal to protect her from Bacchus’s tiger, the Greek god of wine was so contrite that he wept tears of wine over her frozen form, giving amethyst quartz its purple color. Amethyst is also mentioned in the Bible and was believed to bring peace of mind to the wearer.
Perhaps because of its depth and richness, it has always been associated with intense emotion.
March Birthstone: Aquamarine
- RI: 1.577 – 1.583
- Hardness: 7.5 – 8
- Specific Gravity: 2.72
- Species: Beryl
- Optic Character: Double Refractive
- Phenomena: Chatoyancy (rare)
- South America, Africa, China
- Heated to improve color (remove green) – This treatment is permanent and needs no special care.

Imagine a dip in a crystal blue mountain lake – the morning air crisp and expectant, the sky soaring high and cloudless overhead. This is the unique refreshment of Aquamarine.
The name means “ocean water,” and tales of Aquamarine date back to ancient seafaring days. Sailors of old believed that these glittering, watery gems came from the treasure chests of mermaids. Perhaps it’s no wonder that Aquamarine is said to bring luck to all who sail the seas.
Aquamarines are found in a range of blue shades, from the palest pastel to greenish-blue to a deep blue. While the choice of color is largely a matter of taste, the deeper blue gems are rarer. No matter what size, color, or shape of Aquamarine you may desire, we can help you obtain the perfect gem.
Remember that Aquamarine is a pastel gemstone, and color can be quite intense in larger gemstones. Although we strive for the best in any stone, the smaller Aquamarines are often less vivid.
The elegant colored gemstone is the birthstone of March and is a symbol of youth, hope, health, and fidelity. It is believed to calm the mind, body, and spirit. This gemstone was also thought to give wearers knowledge, foresight, and assist in inspiration. Aquamarine has been reputed to cure laziness and insomnia, increase wisdom, provide everlasting youth, and even cure hiccups!
April Birthstone: Diamond
- RI: 2.417
- Hardness: 10
- Specific Gravity: 3.52
- Species: Diamond
- Optic Character: Singly Refractive
- Phenomena: None
- Botswana, Russia, South Africa, Australia, Namibia, Zaire, Brazil, China, Canada, US
- None (natural)

The fire of passion. The perfection of hope. The brilliance of joy. All these are part of a couple’s love for each other – a love that finds its ideal expression in a diamond.
No other stone offers the clarity, brilliance, and breathtaking depth of a diamond. And for centuries, those who wore such stones were believed to share their virtues. Fabulous tales abound of luck the success, fearlessness, and invincibility. Legends of seduction, intrigue, and irresistible attraction.
Diamond is the birthstone for April. A diamond is the most potent symbol of devotion as you begin a life together. And while a gift of diamonds is traditional on the 10th and 16th anniversaries, there’s never a better way to say that your love has only grown stronger, deeper, and more enduring with the passage of time.
Diamonds are also the most classic of all jewels. Their unmatched beauty and elegance make them ideal for marking life’s most important occasion, from the birth of a child to milestones like a graduation or a major promotion. But then, why wait? The gift of a diamond can transform any occasion – or no occasion at all – into a moment sure to be treasured forever.
For further details, be sure to see Diamonds heading EDUCATION.
May Birthstone: Emerald
- RI: 1.577 – 1.583
- Hardness: 7.5 – 8
- Specific Gravity: 2.72
- Species: Beryl
- Optic Character: Doubly Refractive
- Phenomena: Chatoyancy, Asterism (rare)
- Columbia, Zambia, Brazil, Pakistan, Zimbabwe
- Natural and Traditional Oiling

Lush. Exotic. Untamed. This is no polite garden-variety green: Emerald pulses with life and vitality. In its depths beats the heart of the rain forests, its shadows alive with promise, expectation…even danger.
Emeralds are known as the gem of queens and the queen of gems. More valuable than even diamonds, fine-quality Emeralds of significant size are among the world’s most bewitching jewels. Their incomparable dark green color is produced only under extremely rare conditions. Because these conditions also result in tiny cracks and cavities in the stone, inclusion is allowed in top quality Emeralds.
Believed by the ancients to empower the owner with foresight into the future, Emerald is regarded as an amulet for good fortune. Ancient history records Emerald mines near the Red Sea, “Cleopatra’s Mines,” where the Pharaohs gathered gems between 3000 and 1500 B.C. The Incas and Aztecs of South America once worshiped Emerald as a holy stone. And Maharajahs of India, who believed the gem brought luck and restored health, had multitudes of Emeralds in their treasure vaults.
Emeralds can come in different shades of green, from dark leaf green to pale sea green. The most important thing to look for when it comes to emeralds is their color. More vivid stones are more valuable.
June Birthstone: Alexandrite
- RI: 1.746 – 1.755
- Hardness: 8.5
- Specific Gravity: 3.73
- Species: Chrysoberyl
- Optic Character: Doubly Refractive
- Phenomena: Color change
- Brazil, Russia
- None (Natural)


Alexandrite was first discovered in the Ural Mountains of Russia in 1830. Prized immediately for its hypnotic beauty, the stone was named after Czar Alexander II, in honor of his coming of age. Because of its ability to change dramatically in shifting light, Alexandrite has become associated with balance in life, self-esteem, and the ability to experience joy – powers that, according to legend, the stone may impart to its wearers.
Until recently, Alexandrite was more commonly found in very old pieces of jewelry from the 1850s to the early 1900s, when the material was still available from Russia, but the color change was red to green. With the new discovery of rough material from Brazil recently, it is once again commercially available for wear. In incandescent lighting, the stone appears reddish-purple; in fluorescent lighting, the same stone appears a bluish-green.
Mysterious, stimulating, endlessly fascinating, Alexandrite attracts all ages. It is a wonder to behold.
June Birthstone: Pearl
- RI: 1.53 – 1.685
- Hardness: 2.5 – 4
- Specific Gravity: 2.72 – 2.78
- Species: Pearl (Several varieties)
- Optic Character: Doubly refractive
- Phenomena: Orient. Varies from none to very pronounced.
- Japan, China, French Polynesia, Australia, China, America
- Natural and Cultured

Pearls have been an object of desire from the first days of human society, and are treasured not only for their rare beauty, but as symbols of harmony, purity, and wisdom. June birthdays and third and thirtieth anniversaries are celebrated with the gift of Pearls.
Pearls were believed by the ancient Babylonians to have life-giving powers and the ability to restore youth. Old Arabian legend says that I was formed when dewdrops filled with moonlight fell into the ocean and were swallowed by oysters. American Indians found me in the mollusks of the Mississippi River and strung me onto necklaces, adorned their headdresses, and set me into copper ornaments. Down through the centuries, man’s desire for the perfection of Pearls has not waned. The exotic, lustrous skin of Pearls, smooth and silky to the hand and eye, embodies all that is feminine.
Pearls are truly a gift of the sea, and the only gemstone formed within a living creature. Pearls were so cherished by man, that as the sources of natural Pearls became exhausted, he learned to replicate the process created by Mother Nature through cultivation techniques.
No other jewel makes the transition as smoothly from day to evening as Pearls. Pearls come in many beautiful colors, from palest cream and white to rose, lilac, green, gold, gray, and the dramatic Tahitian black. Pearls come in many shapes and sizes and can be acquired in both graduated and uniform strands. They can be purchased singly or in pairs for rings, pendants, and earrings.
July Birthstone: Ruby
- RI: 1.762 – 1.77
- Hardness: 9
- Specific Gravity: 4.0
- Species: Corundum
- Optic Character: Doubly Refractive
- Phenomena: Asterism, Chatoyancy
- Thailand, Myanmar, Kampuchea, Sri Lanka, Kenya, Afghanistan, India, Pakistan, Tanzania, Madagascar, Mozambique
- Heated to improve color – This treatment is permanent and needs no special care.

The “king of gems,” Ruby is one of the world’s oldest and most revered gemstones. It is also one of the rarest, as red is the rarest occurring color in gems. It owes it’s startling color to the presence of the mineral Chromium. Rubies with hardly any inclusions are so rare that large stones of good color fetch higher prices at auction than even diamonds.
Fiery and romantic, showing brilliant depth and intensity, the red hue of Ruby is certain to draw attention. Its symbolic association with passion sends a drop-dead message of glamour and femininity.
The birthstone of July, the ruby has been prized for centuries as a symbol of love and immortality.
Please note: Photo Courtesy of AGTA
August Birthstone: Peridot
- RI: 1.654 – 1.69
- Hardness: 6.5 – 7
- Specific Gravity: 3.34
- Species: Peridot
- Optic Character: Doubly Refractive
- Phenomena: None
- China, Australia, Brazil, Myanmar, Kenya, Mexico, Sri Lanka, Pakistan, US
- None (Natural)

Peridot’s history can be traced back more than 3,500 years when it was prized by the ancient Egyptians. Romans named the gem as the “Evening Emerald,” due to its brilliant color not fading in the lamplight, but instead seeming to glow in the evening hours. Hawaiian legend names peridot as the tears of “Pele,” the volcano goddess of the islands.
Peridot has been credited with a host of magical powers and healing properties, such as protection against nightmares and possessing the power to ward off evil.
Value is closely tied to how evenly distributed the color appears. With inclusions quite common in most stones, the most valuable are the cleanest and greenest. Peridot is the birthstone for August and comes in a variety of sizes and shapes.
Please note: Photo Courtesy of AGTA
September Birthstone: Sapphire
- RI: 1.762 – 1.77
- Hardness: 9
- Specific Gravity: 4.0
- Species: Corundum
- Optic Character: Doubly Refractive
- Phenomena: Asterism, Color change, Chatoyancy (very rare)
- Australia, Thailand, Sri Lanka, Myanmar, India, Kampuchea, Kenya, Tanzania, US, Madagascar, Cambodia, Kashmir
- Heated to improve color – This treatment is permanent and needs no special care.

Sapphire is actually the same mineral as ruby: they are both members of the corundum family and share the same physical characteristics and the same chemical composition. Even though most people consider Sapphire as the pre-eminent blue gemstone, the magnificently versatile Sapphire can be found in a rainbow of colors, spectacular yellows and oranges, vivid pinks, and lavenders, and soothing greens. These diverse colors are referred to as “fancy” color Sapphires.
Beloved for centuries as the ultimate blue gemstone, the ancient Persian rulers believed the Earth rested on a giant blue sapphire whose reflection made the sky blue. The name for Sapphire comes from the Greek name for “blue”. Sapphire has been credited with profound powers such as the ability to protect the wearer against poisons and evil spirits.
The birthstone for September, Sapphire symbolizes trust, sincerity, and loyalty. Sapphire has also been worn an engagement stone, most recently in the case of Lady Diana, the late, former wife of Prince Charles of England. Sapphire is the second hardest mineral after diamond, and it is a very suitable stone for daily wear. Blue and fancy Sapphires are very easy to incorporate as an everyday color for today’s woman.
October Birthstone: Opal
- RI: 1.45
- Hardness: 5 – 6.5
- Specific Gravity: 2.15
- Species: Opal
- Optic Character: Singly Refractive, ADR common
- Phenomena: Play of Color
- Australia, Mexico, US, Ethiopia
- Natural or None

With its pulsating display of fire and color, Opal was long thought to hold magical powers. Opals symbolized hope, innocence, and purity to the Greeks and Romans. Opals were often reserved for royalty. The crown of the Holy Roman Emperor held a superb example, a fiery red Opal called “The Burning of Troy”. This superb Opal was given as a gift from Napoleon to Josephine – forming part of the crown jewels of France. Queen Victoria of England also loved Opals and often presented them as wedding gifts.
Opal is found in several different colors including black Opal (pictured), whose blue, gray, or black body color enhances the play of fire; white or fire Opal, with a lightish or white body color; and crystal Opal, a transparent version with bright color flashes. Boulder Opal has color flashes intertwined with rock matrix. Opals are not faceted but cut into rounded or free-form cabochons that enhance their play of color.
Different in appearance is Fire Opal, a transparent gemstone of brilliant yellow, orange or red, often cut with facets (please see additional listing under Mexican Fire Opal).
October Birthstone: Tourmaline
- RI: 1.624 – 1.644
- Hardness: 7 – 7.5
- Specific Gravity: 3.06
- Species: Tourmaline
- Optic Character: Doubly Refractive
- Phenomena: Chatoyancy, Color change (rare)
- Brazil, Afghanistan, Myanmar, India, Kenya, Madagascar, Mozambique, Pakistan, Sri Lanka, Tanzania, US
- None or Heated to improve color – This treatment is permanent and needs no special care.

Tourmalines occur in many forms as well: several faceted shapes, cabochons (domed), carvings, thin slices called Watermelon Tourmaline (in which the center is pink with an outer green edge), “particolored” (in which the cut gemstone transitions in color shades from two to several shades including, green, blue, colorless, and pink), and “cat’s eye”, in which a vertical line is centered in a dome-shaped stone, appearing as the eye of a cat.
The birthstone for October (along with Opal), Tourmaline legend states that it aids against misfortune and protects travelers against falls. It is also the National Gemstone of the United States (please see individual listings under Tourmaline).
November Birthstone: Topaz
- RI: 1.619 – 1.627
- Hardness: 8
- Specific Gravity: 3.53
- Species: Topaz
- Optic Character: Doubly Refractive
- Phenomena: Chatoyancy
- Brazil
- None (Natural)

Precious Topaz was revered by the Egyptians and Romans, who associated it with the setting sun. In modern times, rich stores of Precious Topaz were discovered in Russia; placed in the jewels of the Russian Czarina’s, the gem earned the name of “Imperial Topaz.”
The mesmerizing hue of Precious Topaz is symbolic of love and affection. And so remarkable is the gemstone’s transparency and brilliance that famous examples have been confused with diamonds.
The birthstone for November, Precious Topaz was derived from a Sanskrit word meaning ” fire.” Topaz has long been believed to promote calm and faithfulness, to protect against enchantment, and to cure insomnia.
November Birthstone: Citrine
- RI: 1.544 – 1.553
- Hardness: 7
- Specific Gravity: 2.66
- Species: Quartz
- Optic Character: Doubly Refractive
- Phenomena: None
- Brazil, Bolivia
- Heat – This treatment is permanent and does not need special care.

Sunny and full of light, this sparkling gem was once thought to protect the wearer against various evils – from snake venom to wicked thoughts and the ability to remain neutral in the conflict. Today, its radiant color is associated with cheerfulness, youth, and vitality.
Citrine ranges in color from slightly golden yellow to an orange and honeyed caramel, resembling Madeira wines. It comes in a wide variety of shapes, large sizes, and is relatively modest in cost.
The birthstone for November (as well as Precious Topaz), is a wise affordable choice!
December Birthstone: Blue Zircon
- RI: 1.925 – 1.984
- Hardness: 7.5
- Specific Gravity: 3.90 – 4.73
- Species: Zircon
- Optic Character: Doubly Refractive
- Phenomena: Chatoyancy (rare)
- Kampuchea, Sri Lanka, Myanmar, Australia, Thailand, China
- Heated to improve color – This process is permanent and needs no special care.

The aqua-blue brightness of Zircon often tinged with a shimmering teal, gives energy and renewal to those who discover this often overlooked gem. Its color is similar to Paraiba Tourmaline, a rare and extremely expensive gemstone that is now an extinct species.
The birthstone for December, Blue Zircon is guaranteed to take your breath away and keep your pocketbook in good standing!
December Birthstone: Tanzanite
- RI: 1.691 – 1.700
- Hardness: 6 – 7
- Specific Gravity: 3.35
- Species: Zoisite
- Optic Character: Doubly Refractive
- Phenomena: Chatoyancy (rare)
- Tanzania
- Heated to improve color – This process is permanent and needs no special care.

Tanzanite’s rarity and exotic origin are also part of its fascination. For this modern gemstone was unknown until 1967 when herdsmen in eastern Africa noticed blue crystals sparkling in the sun. Tanzanite’s dramatic discovery, coupled with its scintillating beauty, caused a worldwide sensation. To date, the world’s only source for the gem remains the hills of northern Tanzania, near Mount Kilimanjaro.
Tanzanite’s dual-color – brilliant blue with hints of purple – makes it both warm and cool. Bold yet beautiful, it is a favorite of both men and women.
The birthstone for December, fine Tanzanite supplies is dwindling and becoming rarer, especially in large sizes. Try to get some while it’s still available!
Gems Charts to Give a Gift
Days of the Week: | |
---|---|
Sunday: | Topaz |
Monday: | Pearl |
Tuesday: | Ruby |
Wednesday: | Amethyst |
Thursday: | Sapphire |
Friday: | Emerald |
Saturday: | Diamond/Turquoise |
Month | Gemstone | Symbolism |
---|---|---|
January | Garnet | Constancy |
February | Amethyst | Sincerity |
March | Aquamarine | Courage |
April | Diamond | Innocence |
May | Emerald | Success/Love |
June | Pearl / Alexandrite / Moonstone | Long Life & Health |
July | Ruby | Contentment |
August | Peridot | Happy Marriage |
September | Sapphire | Clear Thinking |
October | Opal/Tourmaline | Hope |
November | Precious Topaz/Citrine | Fidelity |
December | Blue Zircon/Tanzanite | Prosperity |
Year | Anniversary Gift | Year | Anniversary Gift |
---|---|---|---|
1 | Gold Jewelry | 15 | Ruby |
2 | Garnet | 16 | Peridot |
3 | Pearls | 17 | Watches |
4 | Blue Topaz | 18 | Tanzanite |
5 | Sapphire | 19 | Aquamarine |
6 | Amethyst | 20 | Emerald |
7 | Onyx | 25 | Silver Jubilee |
8 | Tourmaline | 30 | Pearl Jubilee |
9 | Lapis Lazuli | 35 | Emerald Jubilee |
10 | Diamond Jewelry | 40 | Ruby Jubilee |
11 | Turquoise | 50 | Golden Jubilee |
12 | Jadeite | 55 | Alexandrite |
13 | Citrine | 60 | Diamond Jubilee |
14 | Opal | 75 | Platinum |