Gemology 101: The Ultimate Guide To All That Glitters

As anyone who’s seen Moulin Rouge one too many times can tell you, diamonds are a girl’s best friend—but they’re hardly the only gemstone that’s worth singing about.

If you’re in the market for a new piece of jewelry (or just hope that one day you will be), it’s well worth brushing up on your gem knowledge before delving into collections filled with discombobulating names like chalcedony and chrysoprase. And after seasons of sleek silver chokers and ultra-minimal stacking rings, I think it’s high time to again embrace the glamour and individuality of gemstone jewelry.

Plus, at the top of my to-do list on my way to becoming a Fancy Lady is getting informed about fancy jewelry. For instance: What makes a blue diamond different from a sapphire? Where do opals get that pretty, rainbow-y shimmer? How does one go about “culturing” a pearl? (A trip to the Met?)

To help me with this mission, I enlisted some experts on the science, history and mythology behind our favorite gemstones: Gem Gossip‘s Danielle Miele, a certified gemologist, blogger and Instagrammer extraordinaire (you may know her from her popular hashtag, #showmeyourrings), the ultra-creative (and ultra-knowledgeable!) jewelry designers Melissa Joy Manning and Jacquie Aiche, and Jerry Ehrenwald, president and CEO of the International Gemological Institute, the world’s largest certification and appraisal organization.

Chrysoprase

This pale yellow-green stone is part of the quartz family and gets its color from the presence of nickel. “What sets it apart from other quartz like amethyst and citrine is that it is cryptocrystalline,” says Miele. Translation: It’s made up of microscopic crystals that are neither transparent nor visible to the naked eye. According to Aiche, however, the stone may be able to help clear up murkiness elsewhere in your life: “Chrysoprase brings clarity to the wearer; things that were a little mystifying might become crystal clear with a little assist from this stone. It also encourages hope and joy.” And at a far more accessible price than a certain other gimlet-hued gemstone (looking at you, emerald), it may also be the best way to sate a desire for something green and sparkly.

Chrysophase Arc Necklace, $506, Wwake, LuckyShops.com
Chrysoprase Hexagon Ring, $2,875, Jacquie Aiche
Eye Stone Bracelet, $70, Tai

Lapis Lazuli

Ultramarine, Yves Klein Blue—call them what you will, some of the art and fashion worlds’ favorite hues are derived from lapis’ signature deep blue. In fact, per the International Colored Gem Association, the stone itself was regularly ground into a powder to provide the pigment for ultramarine paint until the mid-1800s, when a far cheaper alternative was invented. Without lapis, Vermeer’s “Girl With A Pearl Earring” and swaths of Renaissance-era Virgin Marys would be draped in fabric of a much duller blue. The gem is also distinguished by the tiny golden flecks that give it its “night sky” appearance, which are actually scattered crystals of pyrite (a.k.a. fool’s gold) and can enhance a stone’s value if they’re particularly striking. Lapis can be found at relatively affordable prices, however, and the time might be right to add a piece to your collection. According to Aiche, who counts it among her favorites, “Now is a great time to wear this stone as Lapis heals and purifies (getting you ready for a little spring cleaning…). It brings self-awareness, enlightenment and an open mind.” Not to mention a ton of compliments.

Inward Triangle Trinity Ring In Lapis, $3,750, Jacquie Aiche
Brian Cuff, $515, Uribe, LuckyShops.com
Atiin Lapis Earrings, $165, A Peace Treaty 

Opal

Opals are known for their unique, rainbow-like iridescence (technically called “play of color”), but as Manning points out, they are also an exceptionally diverse stone, with more than a dozen types in existence, ranging from common blue to Mexican fire opal, which flashes bright colors when held to the light. The different types, she says, “are distinct due to color and provenance,” adding that her favorite is the boulder opal, which is the second most precious of Australia’s ample opal offerings (the continent produces more than 90 percent of the world’s supply) and is often cut together with the ironstone in  which it is found, creating a gorgeous Franken-stone of sorts. “To me they kind of look like an aerial photograph of a river or an arid landscape.” As opals develop, she says, they can take on a range of colors depending on their environment. “The actual elements of the stone are the same—it’s just the colors and transparency are different based on the atmosphere in which they’ve grown,” she says. “I guess they’re like people: We’re all the same, but we all look really different.” And as for that superstition that says it’s bad luck to buy one for yourself? Total baloney. As it turns out, Manning explains, the old wives’ tale originated back before jewelers and gemologists knew to how to set common opals: “Opals are soft, and if you’re using them in an unstable setting or the stone hasn’t been stabilized with a backing, they will crack or break. So because people didn’t know that at the time, people weren’t setting them correctly or backing them with a matrix…and the stone would crack when it was worn.” Today, you’re in much safer hands.

Freeform Boulder Opal Necklace, $450, Melissa Joy Manning
Frosted 14K Gold Boulder Opal Eclipse Earrings, $1,940, Lana
Opal Dirae Ring, $115, Unearthen

Pearl

A gem unlike any other, the pearl comes not from a mine, but from inside the shell of an oyster or mussel. Almost all real pearls on the market fall into one of two categories: saltwater or freshwater (where the mollusks were farmed), which can tell you something about the rarity—and therefore, the value—of the pearl. Freshwater pearls are more popular with most designers today, says Miele, in part because they’re simply more abundant. The river- and lake-dwelling mussels used to culture the stones can produce dozens of pearls in a single harvest, while saltwater oysters tend to produce only one. And as for what “culturing” actually means? Well, farmers implant a small “bead nucleus” (usually a polished, spherical shell) into the oyster along with a piece of tissue harvested from another oyster, and wait for nature to run its course. The pearl is actually composed of layers of nacre, which is the substance the mollusk uses to defend itself against foreign objects inside its shell (although you may know it better as “mother of pearl”). In general, the thicker the nacre, the more valuable the pearl—because the process takes time (years, in most cases) and because the mollusks themselves are so small, Miele explains, “really large pearls are actually quite rare.” Natural pearls—those that form in the wild sans human intervention—do exist, but they are exceedingly rare and usually prohibitively expensive (exhibit A: this $1.6 million necklace.)

Pearl Orbit Cuff, $108, Gabriela Artigas, LuckyShops.com
Spike Pearl Pendant, $495, Nektar De Stagni
Belinda Pearl Earrings, $148, Dannijo

Ruby

Rubies and sapphires are both members of the corundum family, and since they are distinguished by color, Miele concedes, “There’s always a fine line between a pink sapphire and a ruby.” Rubies, however, are extremely rare, and most valuable when they are a deep, vivid red. “What we look for is color saturation,” explains Ehrenwald. “How red is the red? How deep is the color? How pronounced is it? So when someone looks at your ring and they see a commercial-quality ruby, it’s purplish red.” In a somewhat cruel twist of fate, the same mineral that gives rubies their sensational color, chrome, is also the reason behind the stone’s scarcity, having caused fissures and imperfections in most of the world’s supply.

Mwa! Necklace, $1,650, Alison Lou
Ruby Pacha Bangle, $785, Ashley Hoffman
Ruby And Gold Midi Ring, $275, Loren Stewart

Sapphire

When you think of a sapphire, odds are you picture a brilliant blue gem (perhaps even the one attached to Kate Middleton’s finger?) And while that is certainly the default, the stone in fact comes in a wide range of hues, from orange to pink to purple, and even color change, a rare sapphire that appears to shift from one shade to another depending on the surrounding light. Also highly coveted are “star sapphires,” stones laced with mineral inclusions that form a star shape when reflecting light. “They are more valuable based on how many points there are in the star,” says Manning, a professed fan of the distinctive stone. “I think those can be a great alternative [to a traditional diamond] as well. They’re hard to find and the really good ones are truly mesmerizingly beautiful.” Unlike diamonds, which have an internationally accepted grading standard, the value of colored gems like sapphires is somewhat more subjective. While those mined in Kashmir are widely accepted to be the most valuable, the IGI’s Ehrenwald clarifies that, “It’s not always about origin, it’s really about the beauty and how someone observes it and if it turns them on or not. Some people like Sri Lankan sapphires because they have a different look than a Burma or a Kashmir or an Australian. They have different looks. Some people like dark sapphires, so you get Thai sapphires or Australian sapphires, and some people like lighter shades of sapphires.” Celebrity approval can also be a factor, he notes: After Princess Diana’s engagement in 1981, demand for the stone spiked significantly. And with Kate in line to be queen, we’re sure the royal’s choice bauble will keep its seat on the throne.

14-Karat Teardrop Hand Bracelet With Diamonds And Sapphires, $730, Sydney Evan
Obi Ring, $75, Elizabeth And James, LuckyShops.com
Pink Sapphires Dots Ear Cuff, $6,527, Delfina Delettrez

Emerald

Emeralds are ancient (some Zimbabwean gems began growing 2,600 million years ago, according to the ICA), venerated (they’ve been buried with pharaohs and inscribed with religious texts) and often seriously expensive—which you can chalk up to the relative rarity of high-quality raw material. They are what’s known in the gem world as a “type three” stone, which means they tend to come out of the mine marred with bubbles and other imperfections. However, says Ehrenwald, gemologists generally take this into account and are less severe when grading their clarity. In certain stones, the inclusions fortuitously form a distinctive pattern, such as that which is only found in the emeralds of Trapiche, Colombia. “Trapiche is the sugar mill grinder that was used in the mills in Colombia, and that pattern of the grinding wheel is what appears in the emerald,” explains Manning. “So it’s a green emerald with a black, almost star pattern, like a wheel within the stone. They’re pretty rare and they’re definitely harder to find. We’ll come back with 12 pieces, as opposed to an opal—we might come back with 1,200 of those.” For the more daring couple, this gem also has potential as a diamond-alternative.

Emerald Hook Earrings, $385, Grace Lee
Emerald And Diamond Pendant Necklace, $3,940, Amrit
Trapiche Emerald Oval Ring, $640, Melissa Joy Manning

Amethyst

While the rich purple hue may project an aura of regality and exclusivity, amethyst is actually a variety of quartz, the most abundant mineral on the planet, and the stone isn’t nearly as rare as some of its precious counterparts. For this reason, Ehrenwald reports that it has picked up in popularity during the recent economic recovery (after all, at $15-20 per carat, why not go for a big one?), though quality and color can vary greatly, from the palest purple to the deepest violet.

Smooth Amethyst Earrings, $1,250, Gabrielle Sanchez
Mineral Pendant, $188, Samantha Wills
Delilah Ring, $1,748, Liz Phillips 

Tourmaline

Tourmaline is something of an “every stone”—it comes in all colors of the rainbow (usually more than one at a time), is found all over the world and no two pieces look exactly alike. Miele is especially fond of the so-called “party colors” like watermelon tourmaline, which garnered its name from its pink center ringed in green. “When the crystal was forming, it picked up different trace elements along the way, and the trace elements are what give gemstones their color,” she explains.

Tourmaline Primavera Ring, $3,980, Lucifer Vir Honestus
Natural Tourmaline Necklace, $13,090, Monique Pean
Spinel, Tourmaline Freeform, Watermelon Tourmaline Five Drop Earrings, $2,340, Melissa Joy Manning