Garnet is 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. 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. Garnet is a rarely treated stone
Mohs scale: 6.5-7.5
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. 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.
Mohs scale: 7
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.
Mohs scale: 7.5-8
You probably already know of the diamond’s toughness. In fact, it’s the hardest gemstone and is made of just one element: carbon.
Its structure makes it 58 times harder than anything in nature and can only be cut with another diamond. While it’s become nearly synonymous with wedding engagements, it’s also the perfect stone for individuals who want something that’s just as appropriate for everyday wear as it is for special occasions.
Diamonds come in several colors, including yellow, red, pink, blue, and green, and range in intensity from faint to vivid. Generally speaking, the more saturated the color, the higher the value.
Historically, the diamond first became a popular gemstone in India, when the Moghuls and Imperial Colony easily mined diamonds from deposits along three major rivers.
While it is known that Diamonds are incredibly hard, it does not mean that they can not chip or break.
Mohs scale: 10
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.
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.
Mohs scale: 7.5-8
June’s third birthstone, moonstone, was named by the Roman natural historian Pliny, who wrote that moonstone’s shimmery appearance shifted with the phases of the moon.
The most common moonstone comes from the mineral adularia, named for an early mining site near Mt. Adular in Switzerland that supplied this gem. This site also birthed the term adularescence, which refers to the stone’s milky glow, like moonlight floating on water.
Moonstone is composed of microscopic layers of feldspar that scatter light to cause this billowy effect of adularescence. Thinner layers produce a bluish sheen and thicker layers look white. Moonstone comes in a range of colors spanning yellow, gray, green, blue, peach and pink—sometimes displaying a star or cat’s eye.
The finest classical moonstones—colorlessly transparent with a blue shimmer—come from Sri Lanka. Since these sources of high-quality blue moonstones have essentially been mined out, prices have risen sharply.
Moonstones are also found in India, Australia, Myanmar, Madagascar and the United States. Indian gemstones—which are brown, green or orange in color—are more abundant and affordably priced than their classical blue counterparts.
Mohs scale: 6
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.
Mohs scale: 9
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.
Mohs scale: 6.5-7
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.
Mohs scale: 9
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.
Mohs scale: 5.5-6
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. 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.
Mohs scale: 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 deemphasize 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.
Mohs scale: 6.5-7
Sources: American Gem Society/ Pictures: GIA