Young or old, male or female, one thing that every person has in common is that everyone has a birthday! There is a unique gemstone that is associated with the month you were born in. Giving a gift of a birthstone is incredibly thoughtful and meaningful. Birthday jewelry is perfect for most any occasion!
What is your birthstone? Find your stone below and learn more about your birthstone:
Mohs Scale: 6.5-7.5
The word "garnet" comes from the 14th Century Middle English word "gernet" meaning dark red. The word is derived from Latin "granatum" which means seed, and is called so because of the gemstone's resemblance to the beautifully red seeds of the pomegranate.
Garnet is actually the name of a group of minerals that comes in a rainbow of colors, from the deep red of the Pyrope garnet to the vibrant green of Tsavorites. Some rare garnets are even blue, colorless, or—most rare of all—change colors in different lights. But the most common color is a beautiful range of reds, from rust colored to deep violet-red. The garnet is a very durable gemstone (6.5-7.5 on the Mohs scale) found all over the world, including Wyoming, Czech Republic, Greece, Russian, Tanzania, Madagascar, Sri Lanka and India.
The folklore on garnet is extensive. Legend has it that the garnet can bring peace, prosperity and good health to the home. Some even called it the “Gem of Faith,” and it’s believed that to those who wear it and do good, more good will come. (Conversely, it was also said to bring very bad fortune to those who commit bad acts while wearing it.)
The garnet also symbolized deep and lasting friendship. With that legend in mind, give a garnet to someone whose friendship you deeply value.
No matter why or how you wear garnet, this beautiful gemstone is perfect for those who share January birthdays and get to start each New Year with a sense of goodwill, happiness, and purpose.
If you’re looking to purchase a garnet for yourself or a loved one, it is a great way to celebrate friendship, toast a 2nd wedding anniversary or recognize the wearer’s January birthday.
Remember, garnets commonly come in a wide spectrum of reds, but can also be green, pink, colorless or blue. The price of the piece will likely increase for more rare colors like green or blue.
Garnets can also be judged along some of the same parameters as diamonds, with clarity and cut affecting the beauty and value of the stone.
It should be noted that some garnets have inclusions that are part of the beauty of the overall stone (like “horsetails” in Demantoid garnets, or Hessonite garnets which sometimes have a “turbulent” look). So you may discover that you like the unique look these inclusions bring to the piece.
Try to find a cut that spreads light evenly over the surface of the gemstone. This will help to bring out the overall beauty and color of the garnet.
No matter which stone or piece you choose, remember that the garnet is known for its durability and richness of color, so your investment will not only have great emotional value but could be a piece that stands the test of time.
Mohs Scale: 7
Amethyst is purple quartz and is a beautiful blend of violet and red that can be found in every corner of the earth. The name comes from the Ancient Greek, derived from the word “methustos,” which means “intoxicated.” Ancient wearers believed the gemstone could protect them from drunkenness.
Amethyst, as previously mentioned, is composed of quartz, which is the second most abundant material found in the Earth’s crust. Amethyst gets its color from irradiation, iron impurities and the presence of trace elements. Its hardness (a 7 on the Mohs scale) is the same as other quartz, which makes it a durable and lasting option for jewelry.
While amethyst is most commonly recognized to be a purple color, the gemstone can actually range from a light pinkish violet to a deep purple that can read more blue or red, depending on the light. Sometimes, even the same stone can have layers or color variants, so the way the gemstone is cut is important to the way the color shows in a finished piece.
Amethyst often occurs in geodes or in the cavities of granitic rocks. It can be found all over the world, including the United States, Canada Brazil and Zambia.
Whether you’re purchasing an amethyst for yourself or a loved one, you’re making an investment in beauty that will stand the test of time. Amethyst makes a great gift for individuals born in February, or as a celebratory milestone for a 6th or 17th wedding anniversary.
Of course, you’re also welcome to purchase amethyst “just because.” It’s a beautiful gemstone that ranges in color from a light pinkish violet to a deep red or blue purple violet and complements a number of metals and settings. It’s a durable gemstone that works well with warm or cool colors, so it’s safe to say it goes well beyond special occasion jewelry and can be worn every day, as well.
Amethyst often has “stripes” or layers of color from how and when it was formed, so it takes a skilled gemologist to cut and polish the stone to show the overall color of the stone evenly. Avoid brownish or rust colored tints to the stone and be careful the color is not too deep or it can appear black in some lights.
Like diamonds, you can also look for clarity in an amethyst. Most gemologists will favor a richly colored stone with some minor inclusions (not eye-visible), since the color of this gem is so highly prized. In lighter colored amethysts, visible inclusions will greatly reduce the value of the gemstone.
Since amethyst is relatively plentiful, the price differential in carat sizes isn’t usually terribly significant, so this can be a great gemstone for statement jewelry pieces (though you may not be able to cost-effectively recreate some of Elizabeth Taylor’s memorable amethyst jewelry or the “Kent Amethysts” owned by the British crown).
Larger rings, earrings or pendants can make a stunning addition to a jewelry collection, but even smaller amethysts can be deeply and richly colored, making subtler pieces beautiful, too.
Mohs Scale: 7.5-8
The serenely colored aquamarine invokes the tranquility of its namesake, the sea. In fact, the name aquamarine is derived from the Latin word aqua, meaning water, and marina, meaning the sea.
Aquamarine is most often light in tone and ranges from greenish blue to blue-green; the color usually is more intense in larger stones, and darker blue stones are very valuable. This gemstone is mined mainly in Brazil, but also is found in Nigeria, Madagascar, Zambia, Pakistan, and Mozambique.
Like emeralds, this gemstone is actually a variety of a mineral called beryl. Large stones have been found all over the world, including one stone found in Brazil that weighed over 240 pounds. Aquamarine grows in large, six-sided crystals that can be up to a foot long, making it a great gem to be cut and polished in larger carats for statement pieces.
Not only is aquamarine one of the March birthstones, it’s also used to celebrate 19th wedding anniversaries. It’s a beautiful stone with little or no yellow in it, so it looks great in many settings with different colored metals and gemstones.
Aquamarine is a beautiful stone to purchase for any occasion, but especially for someone with a March birthday or to celebrate or re-kindle romantic love. The color ranges from nearly clear to a strong dark blue and is a perfect way to communicate affection, tranquility, and peace.
Like diamonds, aquamarine can be judged along the lines of cut, color, clarity, and carat weight. While you’re of course welcome to choose the color that most appeals to you, it’s generally accepted that lighter colored aquamarines are less valuable than the stronger, deeper hues of blue or blue green. Next, take a look at the stone’s clarity. Most cut gems do not have inclusions that are visible to the eye, and some rarer or more expensive aquamarines are available without visible inclusions, as well.
Since aquamarine crystals can grow to be quite large, larger cut gemstones are possible to purchase as a part of beautiful statement pieces. Princess Diana had a famous aquamarine ring and bracelet set, and the Queen has a breathtaking set of aquamarine jewels that include a large tiara, necklace, earrings, and bracelet.
While you may not be looking to buy in the “crown jewels” range, even smaller aquamarines make for lovely solitaires or companion jewels in larger pieces. And, of course, the symbolism or sentiment behind the purchase can make aquamarine priceless to the wearer.
Mohs Scale: 10
The fire of passion. The perfection of hope. The brilliance of joy. All these are part of a couple’s love for one another – 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 and success, fearlessness and invincibility. Legends of seduction, intrigue and irresistible attraction. Perhaps the old tales were true. Today, diamonds remain the most potent symbol of devotion as you begin your life together. And while a gift of diamonds is traditional on the 10th and 16th anniversaries, there’s never been 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 occasions, from the birth of a child to milestones like 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.
When determining a value for a diamond there are specific guidelines called the 4 C’s. The 4 C’s are carat, clarity, cut and color.
How to choose a diamond
Mohs Scale: 7.5-8
As the birthstone for May, the emerald, a symbol of rebirth, is believed to grant the owner foresight, good fortune, and youth. Emerald, derived from the word “smaragdus,” means, quite literally, “green” in Greek.
Like aquamarine, emerald is a variety of beryl, a mineral that grows with six sides and up to a foot in length. Emerald color can range from light green (though there is some argument whether these very light beryls are truly emeralds) to a deep, rich green. Emeralds are also like aquamarine in that the way the color is presents itself in jewelry depends on a good cut by a skilled gemologist.
Most emeralds end up being heat treated to deepen or enhance the color. The deeper or more green an emerald, the more valuable it is. The rarest emeralds will appear to be an intense green-blue.
Emeralds are found all over the world, including Colombia, Brazil, Afghanistan and Zambia. The availability of high-quality emerald is limited; consequently, treatments to improve clarity are performed regularly.
Like the diamond and other gemstones, emeralds can be judged according to the 4Cs: color, cut, clarity and carat weight. These gems are highly prized and intensely colored ones can be quite rare, so make sure that you visit a trusted AGS jeweler who can help you make an informed investment.
Most gemologists agree that it all comes down to color when purchasing an emerald. Color should be evenly distributed and not too dark. Rare emeralds will appear as a deep green-blue, while lighter colored gems are more common (and therefore, often more reasonably priced).
Like other beryls, emeralds often have inclusions that are visible without a microscope. Most gemologists readily accept this about these gemstones and don’t detract too much from the overall value of the stone when inclusions are present. Again, it’s all about the hue and saturation of the gem!
Cut is very important on an emerald because it helps to maximize that desirable green color. Many emeralds are cut into an emerald shape, which helps to make a bright stone with sparkle while minimizing inclusions or fissures.
Unlike some gemstones, which can maintain a relatively standard price range no matter the size, you will see a wide price range between smaller emeralds and larger ones. Some of the most famous emeralds in private collections or museums today are literally hundreds of carats and are considered to be priceless. Angelina Jolie, Elizabeth Taylor, and the British monarchy all have worn famously large and beautiful emerald jewelry.
Mohs Scale: 2.5-4.5
Pearls are the only gemstones made by living creatures. Mollusks produce pearls by depositing layers of calcium carbonate around microscopic irritants that get lodged in their shells—usually not a grain of sand, as commonly believed.
While any shelled mollusk can technically make a pearl, only two groups of bivalve mollusks (or clams) use mother-of-pearl to create the iridescent “nacreous” pearls that are valued in jewelry. These rare gems don’t require any polishing to reveal their natural luster.
Appropriately, the name “pearl” comes from the Old French perle, from the Latin perna meaning “leg,” referencing the leg-of-mutton shape of an open mollusk shell. Because perfectly round, smooth natural pearls are so uncommon, the word “pearl” can refer to anything rare and valuable.
The rarest, and therefore most expensive, pearls are natural pearls made in the wild. The majority of pearls sold today are cultured or farmed by implanting a grafted piece of shell (and sometimes a round bead) into pearl oysters or freshwater pearl mussels.
Pearls are very soft, ranging between 2.5 and 4.5 on the Mohs scale. They are sensitive to extreme heat and acidity; in fact, calcium carbonate is so susceptible to acid that pearls will dissolve in vinegar.
The finest pearls have a reflective luster, making them appear creamy white with an iridescent sheen that casts many colorful hues.
Cultured freshwater pearls can also be dyed yellow, green, blue, brown, pink, purple or black.
Black pearls—which are mostly cultured because they are so rare in nature—aren’t actually black but rather green, purple, blue or silver.
Pearls used to be found in many parts of the world, but natural pearling is now confined to the Persian Gulf waters near Bahrain. Australia owns one of the world’s last remaining pearl diving fleets, and still harvests natural pearls from the Indian Ocean.
Today, most freshwater cultured pearls come from China. South Sea pearls are cultured along the northwestern coastline of Australia, the Philippines and Indonesia.
In many cultures, pearls symbolize purity and innocence, which is why it’s tradition for a bride to wear pearls on her wedding day. Besides being one of three birthstones for June, the pearl is also the birthstone for babies born under the signs of Gemini and Cancer, and frequently gifted on 1st, 3rd, 12th and 30th wedding anniversaries.
Pearls make the perfect gift for babies born in June or under the signs of Gemini or Cancer. As ancient symbols of purity and innocence, pearls are traditionally worn by a bride on her wedding day—making pearl jewelry a great gift to celebrate a bride-to-be or a 1st, 3rd, 12th or 30th anniversary.
If you’re shopping for perfectly round natural pearls, you’ll need patience and a large pocketbook. Most pearls on the market today are produced through culturing, giving pearl buyers a wealth of options.
Most freshwater cultured pearls are made in China, while common saltwater cultured pearls include Akoya, white or golden South Sea, and black Tahitian. Colors can range from creamy white to pink, yellow, brown, purple, blue, green, silver or an iridescent rainbow of hues like a peacock.
Pearls are one of few gems not measured by carats. Luster is the most important aspect of choosing a pearl. The finest pearls are metallic and reflective like mirrors.
Pearls can range in size from 3mm to 13mm. Because pearls do not require polishing or faceting like most gems, finding a pair of pearls that match perfectly in size, color and luster can be more difficult—and more expensive. A matched strand of natural pearls may sell for hundreds of thousands (if not millions) of dollars.
Beware imitation pearls or shell pearls, which are made from conch shells or glass coated with a solution containing fish scales. Rubbing two pearls together will reveal if they are smooth imitation stones, or if they feel gritty from the nacre that comprises natural and cultured pearls.
Gem experts can distinguish natural pearls from cultured pearls by using gemological X-ray equipment. Natural pearls consist entirely of concentric growth rings, while cultured pearls have a solid nucleus of the bead or shell that was implanted to stimulate pearl production.
Mohs Scale: 9
Ruby is the red variety of the mineral corundum, colored by the element chromium. All other colors of gem-quality corundum are called sapphire, which means color is key for this royal stone.
Accordingly, the name “ruby” comes from rubeus, the Latin word for red. In ancient Sanskrit, ruby translated to ratnaraj, which meant “king of precious stones.” These fiery gems have been treasured throughout history for their vitality.
The chromium that gives ruby its red color also causes fluorescence, which makes rubies glow like a fire from within. Paradoxically, chromium is also what makes this gem scarce because it can cause cracks and fissures. Few rubies actually grow large enough to crystallize into fine quality gems, and these can bring even higher prices than diamonds.
Burma’s Mogok Valley historically produced the finest ruby material, famous for its deep blood-red color with purplish hues. These Burmese Rubies, also called Pigeon’s Blood Rubies, command a premium over brownish or orange-tinged varieties from other regions.
The Mong Hsu region of Myanmar began producing rubies in the 90s after discovering that heat treatment improved the color saturation. Other ruby deposits exist in Vietnam, Thailand, India, parts of the Middle East, East Africa and even the United States.
Tough and durable, ruby measures 9 on the Mohs scale. Diamond is the only natural gemstone harder than ruby.
Ruby’s strength and red fluorescence make it valuable for applications beyond jewelry. Both natural and synthetic rubies are used in watchmaking, medical instruments and lasers.
Due to its deep red color, ruby has long been associated with the life force and vitality of blood. It is believed to amplify energy, heighten awareness, promote courage and bring success in wealth, love and battle.
Whether you’re showing your love for someone born in July, or celebrating a 15th or 40th wedding anniversary, there’s no better gift than ruby.
Popular since ancient times, these precious gems are said to rouse the senses, amplify positive energy and guarantee health, wisdom, wealth and success in love.
Like diamonds, rubies are evaluated using the 4Cs, plus size and geographic origin. The most important feature of a ruby is its red color, as other hues of this gem species are considered sapphire. The finest ruby is a vibrant purplish red, losing value (and classification as a ruby) as it leans toward brown, orange or even pink.
Rubies also require good transparency. Opaque rubies are much less valuable, even if they display cat’s eye or asterism.
All natural rubies contain imperfections, like rutile inclusions called “silk.” These can actually increase the value of ruby (when displaying a rare cat’s eye or star effect) and are often used to determine a gem’s authenticity.
The Sunrise Ruby is the world’s most expensive gemstone other than a diamond. A 25.6-carat Burmese Pigeon Blood Ruby set between two diamonds weighing 2.5 and 2.7 carats respectively, it sold at auction in 2015 for nearly $30 million, setting a new record price-per-carat.
Lower quality rubies are heat treated to improve color saturation and minimize inclusions, making these varieties more affordable.
A valuable gift to symbolize passion, protection and prosperity, ruby is the perfect way to express powerful emotions.
Mohs Scale: 6.5-7
Though peridot is widely recognized by its brilliant lime green glow, the origin of this gem’s name is unclear. Most scholars agree that the word “peridot” is derived from the Arabic faridat which means “gem,” but some believe it’s rooted in the Greek word peridona, meaning “giving plenty.” Perhaps that’s why peridot is associated with prosperity and good fortune.
Peridot is the rare gem-quality variety of the common mineral olivine, which forms deep inside the earth’s mantle and is brought to the surface by volcanoes. In Hawaii, peridot symbolizes the tears of Pele, the volcano goddess of fire who controls the flow of lava. Rarely, peridot is also found inside meteorites.
Peridot’s signature green color comes from the composition of the mineral itself—rather than from trace impurities, as with many gems. That’s why this is one of few stones that only comes in one color, though shades may vary from yellowish-green to olive to brownish-green, depending how much iron is present.
Most of the world’s peridot supply comes from the San Carlos Reservation in Arizona. Other sources are China, Myanmar, Pakistan and Africa.
Peridot only measures 6.5 to 7 on the Mohs scale, so while the raw crystal is prone to cracking during cutting, the finished gemstones are fairly robust and easy to wear.
Also known as “the Evening Emerald” because its sparkling green hue looks brilliant any time of day, peridot is said to possess healing properties that protect against nightmares and evil, ensuring peace and happiness. Babies born in August are lucky to be guarded by peridot’s good fortune.
Whether you’re shopping for an August birthday or a 16th wedding anniversary, peridot makes the perfect gift that will leave others green with envy.
Peridot can be assessed with the same criteria as diamonds—using color, clarity, cut and carat weight to determine value.
The finest peridots have a lovely lime green hue without any hints of brown or yellow. Quality gems have no inclusions visible to the naked eye, though dark spots may be evident under a microscope. When you look closely, due to double refraction, you may see two of each facet on a peridot.
Thanks to rich deposits of peridot that were discovered in Pakistan in the 1990s, the gem is relatively inexpensive in smaller grain sizes but prices increase for larger stones. Commercially-mined peridots typically measure six to 13 millimeters, so faceted stones are generally about one carat in size.
Flawless peridots over five carats are particularly rare, though stones as large as 22 carats have been cut from basalt rock in Arizona—where most of the world’s peridot is found. The world’s largest peridot is a 310-carat gem in the Smithsonian Museum in Washington, D.C.
Thankfully, there’s now enough raw material on the market so that the perfect peridot can be found to fit any taste or budget.
Mohs Scale: 9
Although sapphire typically refers to the rich blue gemstone variety of the mineral corundum, this royal gem actually occurs in a rainbow of hues. Sapphires come in every color except red, which earn the classification of rubies instead.
Trace elements like iron, titanium, chromium, copper and magnesium give naturally colorless corundum a tint of blue, yellow, purple, orange or green, respectively. Sapphires in any color but blue are called “fancies.”
Pink sapphires, in particular, tow a fine line between ruby and sapphire. In the U.S., these gems must meet a minimum color saturation to be considered rubies. Pinkish orange sapphires called padparadscha (from the Sri Lankan word for “lotus flower”) can actually draw higher prices than some blue sapphires.
The name “sapphire” comes from the Latin sapphirus and Greek sappheiros meaning “blue stone,” though those words may have originally referred to lapis lazuli. Some believe it originated from the Sanskrit word sanipriya which meant “dear to Saturn.”
Sapphires are found in India, Myanmar, Thailand, Vietnam, Sri Lanka, China, Australia, Brazil, Africa and North America (mainly Montana). Their origin can affect their value as much as color, cut, clarity and carat size.
Due to the remarkable hardness of sapphires—which measure 9 on the Mohs scale, second only to diamond—they aren’t just valuable in jewelry, but also in industrial applications including scientific instruments, high-durability windows, watches and electronics.
Sapphires symbolize loyalty, nobility, sincerity and integrity. They are associated with focusing the mind, maintaining self-discipline and channeling higher powers.
Sapphires make stunning gifts for anyone born in September or celebrating a 5th or 45th wedding anniversary. Whatever your reason for buying sapphire, you can’t go wrong with this brilliant gemstone—whether you’re seeking classical blue or another shade of the sapphire rainbow.
Like diamonds, sapphires are assessed by the 4Cs—color, clarity, cut and carat size—in addition to country of origin.
Color is the key indicator of a sapphire’s price. The highest valued sapphires are vivid blue, sometimes with a violet hue. Secondary hues of green or gray detract from sapphire’s value.
Sapphires come in almost any color—except red, which is classified as ruby. Pinkish orange varieties are known as padparadscha, and these typically have higher per-carat values than other colors of fancy sapphire.
Some sapphires even exhibit color change, shifting from blue in daylight or fluorescent light to reddish purple under incandescent light—much like the color-changing alexandrite.
Blue sapphires typically have better clarity than rubies, though they often have long, thin rutile inclusions called “silk.” Inclusions generally make gems less valuable, but they can actually increase the value of sapphires that exhibit asterism.
Blue sapphires can range in size from a few points to hundreds of carats. Most commercial-quality blue sapphires weigh less than five carats. Large blue sapphires, while rare, are more readily available than large rubies.
The 423-carat Logan Sapphire in the National Museum of Natural History is one of the largest faceted gem-quality blue sapphires ever found. The Star of Adam is the largest blue star sapphire, weighing 1404.49 carats.
Sapphires are often treated with heat to improve color and clarity. Untreated natural gems are somewhat rare and incredibly valuable.
Mohs Scale: 5.5-6
The name “opal” originates from the Greek word opallios, which meant “to see a change in color.” The Roman scholar Pliny used the word opalus when he wrote about this gem’s kaleidoscopic “play” of colors that could simulate shades of any stone.
Opal’s characteristic “play-of-color” was explained in the 1960s, when scientists discovered that it’s composed of microscopic silica spheres that diffract light to display various colors of the rainbow. These flashy gems are called “precious opals;” those without play-of-color are “common opals.”
Dozens of opal varieties exist, but only a few (like Fire Opal and Boulder Opal) are universally recognized. Opals are often referred to by their background “body color”—black or white.
Opal’s classic country of origin is Australia. Seasonal rains soaked the parched outback, carrying silica deposits underground into cracks between layers of rock. When the water evaporated, these deposits formed opal. Sometimes, silica seeped into spaces around wood, seashells and skeletons, resulting in opalized fossils.
Since opal was discovered in Australia around 1850, the country has produced 95 percent of the world’s supply. Opal is also mined in Mexico, Brazil, Honduras, Ethiopia, the Czech Republic and parts of the U.S., including Nevada and Idaho.
The water content of opal can range from three to 21 percent – usually between 6 and 10 in gem-quality material. This, combined with hardness of only 5.5 to 6 on the Mohs scale, makes opal a delicate gem that can crack or “craze” under extreme temperature, dehydration or direct light.
Wearing opal is well worth the extra care, though. For centuries, people have associated this gem with good luck. Though some recent superstitions claim that opals can be bad luck to anyone not born in October, this birthstone remains a popular choice.
Opal has been a good luck charm for centuries—though recent superstitions consider it lucky only for people born in October, and unlucky to anyone else.
However, opal’s kaleidoscopic play-of-color can suit many changing moods and tastes to make this gem appropriate for anyone. It is also the traditional gift to celebrate 14th wedding anniversaries.
Like diamonds, opals can be evaluated by color, clarity, cut and carat weight. But these unique gems also have several additional conditions to consider.
Color - Color is the key factor of opal quality: both the background “body color” and the flashing “play-of-color.” Dark backgrounds provide more contrast against vivid play-of-color, making black opal more highly valued than milky white varieties.
Play-of-color is measured on a brightness scale of 1 to 5, from faint to brilliant. Warm colors like red and orange are generally rarer and more valuable than common blues and greens, although color range and coverage also play a role.
Pattern - Pattern is another factor unique to opal. Descriptive names like stained glass, peacock, rolling fire and Chinese writing distinguish opal patterns. Gemologists typically prefer large, concentrated patches over small specks.
Clarity - Different opal varieties have varying clarity standards. Crystal opals should be transparent, while opacity makes black opals more valuable. A cloudy, milky haze lowers any opal’s value, and may indicate instability.
Due to high water content, opal can easily crack or “craze” under extreme temperatures, dehydration or direct light. Crazed opal sells at much lower prices, and is more susceptible to fracture. Even high-quality opal demands delicate care.
Cut - Fine opals are often cut into irregular shapes to emphasize play-of-color. When possible, opals should be cut cabochon with rounded domes. But most opal comes in thin layers, which are commonly mounted on another dark stone like onyx or obsidian (as a doublet) and sometimes capped with clear glass or plastic (as a triplet) to make this fragile gem more wearable.
Opals may be treated with wax, oil, smoke, plastic or other additives to enhance luster.
Mohs Scale: 7-7.5
The name "tourmaline" comes from the Sinhalese words tura mali, which mean "stone of mixed colors." As its name implies, tourmaline stands apart from other gems with its broad spectrum of colors in every shade of the rainbow.
Tourmaline is not one mineral, but a fairly complex group of minerals with different chemical compositions and physical properties. Certain trace elements produce distinct colors, and many resulting varieties have their own names:
- Schorl or black tourmaline is rich in iron, which causes dark shades from deep brown to bluish-black. This variety makes up 95 percent of all tourmaline, though most of it isn’t gem-quality. Schorl, in particular, is said to have protective powers against harmful radiation, toxins and anxiety.
- Dravite or brown tourmaline is rich in magnesium, which causes colors ranging from brown to yellow. It’s named for the Drave District of Carinthina (now Slovenia) where it’s found.
- Elbaite offers the widest range of gem-quality tourmaline colors, due to lithium traces combined with other coloring elements:
- Rubellite or red tourmaline is caused by manganese; but if the color becomes less vibrant under different light sources, it may be called pink tourmaline.
- Indicolite or blue tourmaline can appear purplish blue or bluish green, depending on the amount of iron and titanium.
- Verdelite or green tourmaline can resemble emerald, but if its color is caused by chrome and vanadium, it’s called a chrome tourmaline.
- Paraíba tourmaline is a vividly colored purplish or greenish blue variety found in Paraíba, Brazil. It’s the most recently discovered, and because of its desirably intense colors, it’s one of the most valuable.
- Achroite or colorless tourmaline is rare.
- Parti-colored tourmaline displays more than one color, due to chemical fluctuations during crystallization. A common color combination is green and pink. These are often cut in slices to reveal a red center surrounded by a green rim, earning the name “watermelon tourmaline.”
Tourmaline is mined in Brazil, Sri Lanka, Nigeria, Mozambique, Madagascar, Afghanistan, Pakistan and the U.S.—mainly Maine and California.
Tourmaline is desirable because of its sheer range of color options. Combined with a good hardness of 7 to 7.5 on the Mohs scale, tourmaline makes very wearable jewelry.
One of this gem’s most impressive traits is its ability to become electrically charged through heat (pyroelectricity) and through pressure (piezoelectricity). When charged, tourmaline can act as a magnet by oscillating, and by attracting or repelling particles of dust.
Ancient magicians used black tourmaline as a talisman to protect against negative energy and evil forces. Today, many still believe that it can shield against radiation, pollutants, toxins and negative thoughts.
No two tourmaline gems are exactly alike, which makes this a one-of-a-kind gift for any individual—especially someone celebrating an October birthday or an eighth wedding anniversary.
With a wide variety of colors, qualities and sources available, there’s tourmaline to suit a range of styles and budgets. Like diamonds, tourmaline is evaluated by the criteria of: color, clarity, cut and carat weight.
Color - In general, darker toned tourmaline that appears black is priced much lower than brightly colored material. Rubellite tourmaline, in shades of pink or red, is one of this gem’s most desirable colors.
Green and blue tourmaline is also popular, though the most striking shades of these colors come from Brazil’s exotic Paraíba tourmaline. At about $10,000 per carat, this is the most valuable variety of tourmaline.
Clarity - Inclusions are common in tourmaline, because liquids can get trapped as bubbles during crystallization. It’s not uncommon for red or pink tourmaline to display visible inclusions, but inclusions can drastically lower the value of other colors.
Some tourmaline material, especially rubellite, undergoes heat treatment to improve color. Other tourmaline is clarity-enhanced to remove inclusions, which can significantly lower the value.
Cut - Because tourmaline forms in slender, columnar crystals, many finished gems have long, irregular shapes.
Tourmalines tend to absorb light down the length of a crystal, rather than across it. This makes these gems “pleochroic,” which means they appear different colors from different directions—so the cut is critical.
Carat Weight - Paraíba tourmaline is rare in sizes larger than one carat. But with these stones, color is more highly valued than size, so a small, brightly colored gem is preferred over a large, dark one.
With such a wide range of tourmaline options available—from the common, inexpensive schorl to the highly valued Paraíba—the price of these gems can vary greatly
Mohs Scale: 7
November’s second birthstone, citrine, is the variety of quartz that ranges from pale yellow to brownish orange in color. It takes its name from the citron fruit because of these lemon-inspired shades.
The pale yellow color of citrine closely resembles topaz, which explains why November’s two birthstones have been so easily confused throughout history.
Citrine’s yellow hues are caused by traces of iron in quartz crystals. This occurs rarely in nature, so most citrine on the market is made by heat treating other varieties of quartz—usually the more common, less expensive purple amethyst and smoky quartz—to produce golden gems.
Brazil is the largest supplier of citrine. Other sources include Spain, Bolivia, France, Russia, Madagascar and the U.S. (Colorado, North Carolina and California). Different geographies yield different shades of citrine.
With a hardness of 7 on the Mohs scale, citrine is relatively durable against scratches and everyday wear-and-tear—making it a lovely option for large, wearable jewelry.
Citrine is sometimes known as the “healing quartz” for its ability to comfort, soothe and calm. It can release negative feelings, spark imagination and manifest fresh beginnings. It’s even called the “merchant’s stone” for its tendency to attract wealth and prosperity.
Whether shopping for a November birthday, a 13th wedding anniversary, or just an affordable piece of jewelry to complement any style, citrine makes a perfect gift.
Citrine is one of the most affordable and abundant gemstones on the market. Even fine, large gems are modestly priced, which means everyone can find citrine to fit their budget.
These gems can be evaluated by the same factors as diamonds. Because the majority of citrine gems on the market have been heat treated—and because it takes an expert to detect these enhancements—it’s wise to shop with an AGS jeweler who can help you choose the best gem.
The finest citrine gems are saturated with yellow, orange and reddish hues, while stones of lower value appear pale or smoky. Earth-tones of amber brown are also increasingly popular.
Because these colors are rare in nature, most citrine is created by heating less expensive varieties of quartz, including amethyst and smoky quartz, to produce yellow gems. Most citrine on the market has been heat treated.
Citrine is readily available in sizes up to 20 carats—and, because its price doesn’t rise exponentially with carat weight, big gems are relatively inexpensive.
At its largest, citrine can weigh hundreds and even thousands of carats, like a Brazilian stone at the Smithsonian Institution weighing 2,258 carats.
Thanks to the abundance of large citrine, and the treatment methods that turn less expensive stones into this yellow gem, it’s easy to find citrine at a good price.
Mohs Scale: 6.5-7
Tanzanite is the exquisite blue variety of the mineral zoisite that is only found in one part of the world. Named for its limited geographic origin in Tanzania, tanzanite has quickly risen to popularity since its relatively recent discovery.
Zoisite had been around more than a century and a half before this rare blue variety was found in 1967. Trace amounts of vanadium, mixed with extreme heat, cause the blue color – which ranges from pale blue to intense ultramarine with violet undertones.
Due to pleochroism, tanzanite can display different colors when viewed from different angles. Stones must be cut properly to highlight the more attractive blue and violet hues, and de-emphasize the undesirable brown tones.
The majority of tanzanite on the market today is heat treated to minimize the brown colors found naturally, and to enhance the blue shades that can rival sapphire.
Tanzanite is still only found on a few square miles of land in Tanzania, near majestic Mount Kilimanjaro. Its price and availability are directly tied to mines in this region.
Tanzanite measures 6.5 to 7 on the Mohs scale of hardness – which is not nearly as hard as the sapphire it often substitutes. Given its vulnerability to scratch during daily wear and abrasion, tanzanite is better suited for earrings and pendants than rings.
Between its deep blue color and its limited supply, tanzanite is treasured by many – whether one is born in December or not!
There are many motivations to buy tanzanite, whether to celebrate a December birthday, to commemorate a 24th wedding anniversary, or simply to enjoy the gems rare, vibrant blue. It even serves as a less expensive substitute for sapphire.
Most tanzanite on the market today gets its blue color from heat treatment, which minimizes the stone’s natural brown hues. Treated tanzanite has become the norm, so although it’s undetectable, it’s usually assumed.
Color, of course, is tanzanite’s most prized trait, especially when it’s deeply saturated blue with violet hues. Paler shades are less expensive.
Tanzanite is pleochroic, which means it displays different colors from different angles. So the cut significantly influences the color, which determines the price. Cutting a stone to emphasize the blue may waste more of the rough, but because this color is more valuable than violet, the cutter may choose a small fine-colored blue gem over a larger violet one.
Most faceted tanzanite weighs less than five carats. Stones heavier than 50 carats are rare, although The Smithsonian Institution’s collection includes a faceted 122.7-carat tanzanite. The world’s largest rough tanzanite weighed 16,839 carats.
Because tanzanite is only found within a few square miles in Tanzania, its price and availability can fluctuate sharply, depending what happens there.
Although it doesn’t have a long history of admiration like some gems, tanzanite didn’t take long to rise the ranks. Between its exclusive origin, finite supply and intense blue beauty, tanzanite continues to grow in popularity.
December: Blue Topaz
Mohs Scale: 8
According to a well-known industry magazine, Colored Stone, blue topaz has become the 2nd most popular colored gemstone (sapphire is consistently number one).
This is not surprising. Topaz is a very hard material - 8 on the Mohs hardness scale - and blue topaz is a very pretty stone that is available in a wide range of vivid hues with a striking vitreous luster. It is also a very affordable gem when compared to the price per carat of similar colored gemstones such as aquamarine.
At the same time, blue topaz is a gem that is not well understood by many buyers and some recent controversy in the USA has led some buyers to rethink their blue topaz purchases. In this case, access to the correct information can help blue topaz customers make informed decisions about whether to buy blue topaz or not.
There are two important things to know about blue topaz. The first thing is that while topaz is very hard, it is not the most durable gemstone. That's because it has perfect cleavage, a property it shares with diamond. That means it can be chipped or split by a sharp blow, so it should be protected from hard knocks.
The second important thing is that topaz does not occur naturally in the deeply saturated blues you find on the market today. Blue topaz in nature is very rare indeed and tends to be a very pale blue. The vivid blues available on the market have all been produced by treating white topaz - with irradiation and often also with heat. The color change is permanent and stable, but recently there has been some controversy about the safety of this treatment for the consumer.
There are three different irradiation methods used to produce blue topaz. One method, used to produce a very pale blue hue is exposure to a gamma ray source in a cobalt irradiator. This method does not cause gemstones to be radioactive. The second method is electron bombardment in an accelerator. This is also known as 'linac' treatment and produces the color seen in 'sky blue' topaz. The third method of irradiation exposes topaz to fast neutrons in a nuclear reactor. This produces the darker hues known as 'London blue'.