The folklore around opal gemstones has changed over the centuries. It has long been associated with hope, happiness, innocence, and luck.
According to Arabic legend, opals fell from the sky in bolts of lightning. Greek mythology stated that opals originated from Zeus’ joyful tears after winning the battle against the Titans. Meanwhile, Australian aborigines believed that the Creator came to Earth on a rainbow, leaving these colorful stones where his feet touched the ground.
Aztecs named fire opal after Quetzalcoatl, their feathered-serpent diety. They believed the “Stone of the Bird of Paradise” could foster creativity and beginnings. They felt it could also bring about necessary destruction.
People in the Middle Ages work opal gemstones to bring them luck. They believed that the color-changing opal possessed the powers of each gemstone whose color appeared in its sheen.
However, that perception changed with the 1829 publication of Sir Walter Scott’s book, “Anne of Geierstein.” The story featured an enchanted princess who wore an opal that changed colors with her moods. But when a few drops of holy water extinguished the stone’s magic fire, the woman soon died. People began associating opals with bad luck. Within a year after publication of Scott’s book, opal sales in Europe fell by 50 percent.
Other stories of bad luck were told through the years. For example, Spain’s King Alfonso XII was gifted an opal ring for his wedding. After giving it to his wife, she died. The ring was then given to his grandmother, siter, and sister-in-law, each of them also dying when in possession of the ring. King Alfonso was the last to wear the opal, dying shortly after. These deaths could have been attributed to the cholera epidemic at the time, but the legend of the cursed opal persists.
When opal deposits were discovered in Australia after 1850, the gemstone’s perception changed yet again. The country started to produce 95 percent of the world’s opal supply and many of the most beautiful specimens. People once again clamored to wear opal jewelry.
There are several varieties of gemstones that display optical phenomena, which describes the many ways light interacts with the structural features or inclusions (internal characteristics) in the gemstone. Often these gemstones will be fashioned in a particular way that best displays these effects.
The science of optical phenomena can be fascinating, although the mystery and allure of these effects are what initially attract us! Below are six of the most familiar (and magical) displays of optical phenomena in gemstones.
Play-of-Color
Play-of-color is created by a combination of diffraction and interference, and is the result of the microstructure of opal: the chameleon of a thousand colors and October’s birthstone!
Opals are made up of many layers of small, stacked spheres of silica. These spheres diffract light, splitting it into a spectrum of colors. The layers of these spheres create interference allowing certain colors to dominate, depending on the angle the opal is viewed.
Opal and tsavorite ring, by ASBA USA, Inc.
Black opal and diamond earrings, by Dilamani.
Australian opal and diamond pendant, by Parlé Gems.
Asterism
Asterism, or stars, relates to the four- or six-rayed star pattern of light produced by the fibrous inclusions, elongated needles, or growth tubes in a gemstone. This singular, celestial-like phenomenon is best seen in a gemstone cut en cabochon.
Purple star sapphire, pin sapphire, and diamond ring, by Omi Privé.
Star sapphire, blue and yellow sapphire, and diamond brooch, by Ricardo Basta Fine Jewelry.
Ruby and star sapphire halo ring, by Fine Jewels of NYC.
Chatoyancy
Chatoyancy [sha-TOY-an-cee] is also known as “cat’s eye.” Fine needle-like or fibrous inclusions within the gemstone are what causes this effect. Again, stones fashioned as cabochons display this effect the best.
Cat’s Eye indicolite tourmaline and rubellite ring by AG Gems.
Chrysoberyl cat’s eye ring, from Gleim the Jeweler Estate Collection.
Tiger Eye and diamond ring displaying chatoyancy by NEI Group
Color Change
A small number of gemstones display the color change optical phenomena. Depending on the lighting environment, the color change appearance can vary due to the shifting wavelengths. The technical term for this is photochromism or photochroism; “color-change” is a lot easier to say!
The best-known color changing gemstone is alexandrite. When viewed in sunlight, it appears greenish. When placed under incandescent light, it appears reddish. Other varieties of color-changing gemstones include sapphire, garnet, spinel, diaspore, and tourmaline.
Alexandrite and diamond ring, by AG Gems.
Alexandrite and diamond ring, by TAKAT.
Alexandrite and diamond ring, by JupiterGem.
Adularescence
Adularescence is the phenomenon typically seen in moonstone, which is a member of the feldspar family. It produces a billowy soft blue to milky white light that appears to move across the gemstone. This occurs when light hits the alternating layers of albite and orthoclase, which are two differing forms of feldspar within the gem.
The layers of feldspar interfere with the light rays causing them to scatter and the eye to observe adularescence. The effect is best seen when the gemstone is cut en cabochon [en CAB-ah-shawn]—that is, with a polished, domed top and a flat or slightly rounded base.
Moonstone and diamond baguette ring, by Lika Behar Collection.
Moonstone, aquamarine, and diamond pendant, by Omi Privé.
Blue zircon and moonstone drops earrings, by Yael Designs.
Labradorescence
Labradorscence [lab-ra-dor-es-cence] is an optical characteristic often seen in labradorite. The effect is a spectacular play-of-color that is metallic or iridescent, displaying blue, green, red, orange, and yellow. This is an interference effect within the gemstone caused by internal structures that selectively reflect only certain colors.
Oval shaped labradorite ring with diamond accents, by Tacori.
Labradorite and diamond pendant necklace, by NEI Group.
Labradorite, moonstone, and diamond earrings, by Lika Behar Collection.
When it comes to color choices, October’s birthstones give you some amazing choices. Whether you choose opal or tourmaline, you’ll get a display of exciting and intense colors, making them popular choices for jewelry designers and collectors.
Opal
The name “opal” derives from the Greek opallos, meaning “to see a change (of color).” They range in color from milky white to black with flashes of yellow, orange, green, red, and blue. An opal’s beauty is the product of contrast between its color play and its background.
Opal is a formation of non-crystalline silica gel that seeped into crevices in the sedimentary strata. Through time and nature’s heating and molding processes, the gel hardened into the form of opals. The opal is composed of particles closely packed in spherical arrangements. When packed together in a regular pattern, a three-dimensional array of spaces is created that gives opal its radiance.
Approximately 90 percent of the world’s precious opal comes from Australia. The following are other countries that produce precious or fancy varieties: Brazil, Mexico, United States, Hungary, Peru, Indonesia, Honduras, Guatemala, Nicaragua, Slovakia, Czech Republic, and Ethiopia.
Each opal is totally unique, like fingerprints!! To get a really good look at the opals in these designs, click on the images below for a larger view.
Blue-green black opal and diamond bracelet, by Lightning Ridge Collection.
White opal, aquamarine, and diamond pendant, by Yael Designs.
Australian black opal and diamond ring, by Parlé Gems.
Opal, blue sapphire, and diamond vintage-inspired earrings, by Beverley K.
Tourmaline
Since tourmaline is available in a wide variety of colors, it is ideally suited to almost anyone’s taste. It is known for displaying several colors in the same gemstone. These bi-color or tri-color gems are formed in many combinations; the gemstones with clear color distinctions are highly prized.
Tourmaline is found in many localities including Brazil, Afghanistan, East Africa, and the USA.
The following designs feature the varying hues of tourmaline. Click on the images to see a larger view.
Cuprian elbaite tourmaline and diamond ring, by Omi Privé.
Brazilian blue tourmaline and diamond ring, by AG Gems.
Tourmaline and diamond flower pendant, by Atlantic Diamond Company.
Mint tourmaline and diamond ring, by Carizza.
If you are shopping for opal or tourmaline jewelry, click here to search for an American Gem Society (AGS) credentialed jeweler near you.
We often share beautiful images of American Gem Society members’ jewelry. Today, we wanted to take that a step further and give you a sneak peek into their passion for jewelry, the symbolism it represents, and the way it makes them feel. In some cases, we just wanted to give you a glimpse of their humor, with jewelry as their much-adored punchline.
To achieve all that, we asked these five members to give us a quote about jewelry, along with an image of one of their favorite pieces. Enjoy!
Opal brooch from Paula Crevoshay.
Pink tourmaline pendant from Sharon Wei Designs.
Moonstone, sapphire, and diamond ring from Omi Privé.
Custom-designed ring from Michaels Jewelers.
Diamond engagement ring by Tacori.
To find some jewelry inspiration of your own, visit your local American Gem Society (AGS) jeweler. Ask your AGS jeweler if they have a personal saying or a favorite quote about jewelry! You can ask them to show you one of the above pieces or something that inspires you and your imagination. Visit ags.org/findajeweler.
There are several varieties of gemstones that display optical phenomena, which describes the many ways light interacts with the structural features or inclusions (internal characteristics) in the gemstone. Often these gemstones will be fashioned in a particular way that best displays these effects.
The science of optical phenomena can be fascinating, although the mystery and allure of these effects are what initially attract us! In this article, we’ll discuss six of the most familiar (and magical) displays of optical phenomena in gemstones.
Adularescence
Adularescence is the phenomena typically seen in moonstone, which is a member of the feldspar family. It produces a billowy soft blue to milky white light that appears to move across the gemstone. This occurs when light hits the alternating layers of albite and orthoclase, which are two differing forms of feldspar within the gem.
The layers of feldspar interfere with the light rays causing them to scatter and the eye to observe adularescence. The effect is best seen when the gemstone is cut en cabochon [en CAB-ah-shawn]—that is, with a polished, domed top and a flat or slightly rounded base.
Burmese moonstone ring by Michael Schofield & Co.
Moonstone and diamond ring by United Color Gems.
Asterism
Asterism, or stars, relates to the four- or six-rayed star pattern of light produced by the fibrous inclusions, elongated needles, or growth tubes in a gemstone. This singular, celestial-like phenomenon is best seen in a gemstone cut en cabochon.
Blue star sapphire by Suna Bros.
Pink star sapphire by Suna Bros.
Chatoyancy
Chatoyancy [sha-TOY-an-cee] is also known as “cat’s eye.” Fine needle-like or fibrous inclusions within the gemstone are what causes this effect. Again, stones fashioned as cabochons display this effect the best.
Tiger Eye and diamond ring displaying chatoyancy by NEI Group
Cat’s Eye indicolite tourmaline and rubellite ring by AG Gems.
Color Change
A small number of gemstones display the color change optical phenomena. Depending on the lighting environment, the color change appearance can vary due to the shifting wavelengths. The technical term for this is photochromism or photochroism; “color-change” is a lot easier to say!
The best-known color changing gemstone is alexandrite. When viewed in sunlight, it appears greenish. When placed under incandescent light, it appears reddish. Other varieties of color-changing gemstones include sapphire, garnet, spinel, diaspore, and tourmaline.
Alexandrite cats’ eye framed by alexandrite and diamond ring by Omi Prive.
Alexandrite and diamond ring by Takat.
Labradorescence
Labradorscence [lab-ra-dor-es-cence] is an optical characteristic often seen in labradorite. The effect is a spectacular play-of-color that is metallic or iridescent, displaying blue, green, red, orange, and yellow. This is an interference effect within the gemstone caused by internal structures that selectively reflect only certain colors.
Labradorite ring by Lika Behar Collection.
Labradorite pendant by Lika Behar Collection.
Play-of-Color
Play-of-color is created by a combination of diffraction and interference and is the result of the microstructure of opal: the chameleon of a thousand colors!
Opals are made up of many layers of small, stacked spheres of silica. These spheres diffract light, splitting it into a spectrum of colors. The layers of these spheres create interference allowing certain colors to dominate, depending on the angle the opal is viewed.
Black opal and diamond ring from Lightning Ridge Collection by John Ford.
Australian black opal and diamond ring by Parle.
Are you ready to see some of these displays in person? Visit a credentialed AGS jeweler near you and ask to see some gemstones that exhibit optical phenomena!
Gemstones are beautiful. Everyone knows that! They are flowers of the mineral world, treasures from deep within the Earth.
Most of the time.
There are some gems that are a special breed of stellar minerals. Interstellar minerals that is!
That’s right, there are some amazing gemstones that come from the stars above, or have been found on other planets. These gems aren’t just rare, durable and beautiful; they are (literally) out of this world!
Opal
This incredible pendant by Dilamani Jewelry features Black Opal, which is, thankfully, found right here on Earth!
Opal is comprised of a silica gel substance, usually with a small percentage of water present. The silica forms microscopic spheres that stack upon each other to form opal.
Opal deposits are usually found in cracks and fissures; places where the silica was allowed to seep long ago. Usually, the “gel” is a byproduct of an acidic water-based compound. We know of our opals here on Earth, but what about on Mars?
In 2007, the Mars rover Spirit discovered many deposits of a silica-based rock that looked an awful lot like opals. NASA confirmed it was silica by using false color imaging and the spectrometer, which collects approximately 544 colors (wavelengths) of reflected light to detect minerals on the surface. The minerals are most prominent on outcroppings and in cliff basins in one section of the planet.
These were a surprising and important find on our neighboring red planet because it proves there was, at least at one time, water on the surface.
Perhaps someday they will be able to obtain a sample of this Martian Opal and take a closer look. Will it look like our opals or will it stun us with a different kind of beauty?
For now, they often call it Opaline Silica and eagerly study what they can of this Martian feature as it might hold clues to Mars many ages ago.
Peridot
Though peridot’s remarkable green hue looks out of this world, these sterling silver peridot post earrings by Colore|SG belong to our world.
Peridot is the gem variety of the mineral olivine with the chemical formula (Mg, Fe)2SiO4 – magnesium, iron, silicon, and oxygen. It’s the birthstone of August and is famous for its almost shockingly energetic green color.
On Earth, this gem is found in igneous rocks. Not on Earth, you might see it on a meteorite! The gems have been on pallasite, and around, meteorite impact craters.
The interesting thing to note is that peridot can’t handle super high temperatures, so the outer “shell” of meteorite must have protected it and burned off instead, as it entered the atmosphere.
It is also been observed as interstellar dust. This “dust” is seen in the tails of comets, the disks around young stars, and at the sites of impact craters.
This evidence suggests that the mineral olivine quite possibly was present at the creation of many planets. Perhaps even our own.
Usually, the peridot found on meteorites is small and pale in color, due to the extreme conditions from once it came. GIA laboratories ran a series of tests on the “space” versions of peridot and found key differences in the chemical makeup of the stones, meaning they can always tell if it’s an Earth grown peridot or a visitor from the stars.
The gemstone is often called the stone of sun, maybe that’s a little more literal than we thought.
Quartz and Feldspar
This futuristic pendant features the earthly gemstones bubble quartz, moonstones, and diamonds. Designer Mark Schneider Design won 2nd place for Design Excellence in the 2013 MJSA American Vision Awards.
Quartz and feldspar are two of the most common minerals found on Earth, and makeup not only gemstones such as amethyst, citrine, chalcedony, and moonstone (among others,) but also sand, marble, ceramics, and plastics.
Quartz and feldspar are massive groups of minerals, and since it’s abundant on Earth, we fully expect to see it elsewhere in the universe!
But what might we see if we find these rocks far, far away?
Will we find a bright blue quartz, naturally colored?
A giant moonstone spire that stands taller than a skyscraper?
An entire planet of nothing but crystal?
No one is sure but the possibilities are endless!
The presence of these minerals tells us that other worlds may not be as different as our own, despite appearance. They were all formed in the same universe, after all.
“Diamonds”
Many types of “diamonds,” or something kind of like them, have been found. Some of these minerals are made of carbon but form in a different crystal structure. Since the crystal structure is unique to diamonds and is partially responsible for how tough and durable diamonds are, these stones have a key difference.
Others are small pieces, considered dust. There’s even some that form flat-like sheets, instead of how they form here on Earth.
There’s a bit of a debate if any of these can truly be called “diamonds,” but either way, they are unlike the gems we have here on Earth.
Glass
Multiple forms of glass have been found at impact craters, but the interesting thing about them is that they are often colored. We tend to think of glass as clear, transparent, but the majority of “natural” glass formed by impacts is green! Some of this is called Moldavite.
Discoveries are happening daily about the world beyond our own, and who knows what’s next.
Perhaps someday in the near, or distant, future, we’ll be talking to clients about setting “space” stones into rings, and working on marketing some rare mineral from a million light years away.
With the variety of minerals on Earth alone, the sky’s not even the limit on what we could discover!
Here’s to the rare, durable and beautiful gemstones that make our planet special.
And, apparently, other planets, too.
Isabelle Corvin is an AGS Certified Gemologist (CG) who is the Staff Gemologist at Panowicz Jewelers. Since she was 14-years-old, she knew she wanted to be a gemologist. Ms. Corvin also writes for Panowicz Jewelers’ blog.
ASBA USA, Inc. is a prime supplier of Tahitian cultured pearls and finished diamond, colored stone, and cultured pearl jewelry.
For over 25 years, ASBA USA has been owned and operated by the Israileff family and are long-time members of the American Gem Society. Joshua, Nathan, and Nicolai Israileff carry on their family’s tradition of providing fine quality jewelry.
The following images are just a mere sampling of the artistic, whimsical, and one-of-a-kind designs ASBA USA creates with pearls—their specialty—or a variety of gemstones.
Mint tourmaline and diamonds set in yellow gold.
Right hand ring featuring pink and yellow sapphires. This ring can be customized with any gemstones!
White South Sea baroque pearl wrapped in a diamond bow.
Tahitian pearls drop from diamond and gemstone butterflies.
A one-of-a-kind drop Ethiopian opal pendant with an enhancer bale and diamonds.
Custom eternity band of amethyst and blue topaz.
A 15-17mm Keshi Tahitian pearl set in rose gold with a diamond halo.
Rubellite and yellow diamonds set in 18k rose gold.
If you’d like to see more designs by ASBA USA in person, contact a credentialed AGS jeweler near you.
October features two incredible birthstones: opal and tourmaline. They each display an exciting and intense array of colors, making them popular choices for jewelry designers and collectors.
Opal
The name “opal” derives from the Greek Opallos, meaning “to see a change (of color).” They range in color from milky white to black with flashes of yellow, orange, green, red, and blue. This October’s birthstone beauty is the product of contrast between its color play and its background.
Opal is a formation of non-crystalline silica gel that seeped into crevices in the sedimentary strata. Through time and nature’s heating and molding processes, the gel hardened into the form of opals. The opal is composed of particles closely packed in spherical arrangements. When packed together in a regular pattern, a three-dimensional array of spaces is created that gives opal its radiance.
Approximately 90 percent of the world’s precious opal comes from Australia. The following are other countries that produce precious or fancy varieties: Brazil, Mexico, United States, Hungary, Peru, Indonesia, Honduras, Guatemala, Nicaragua, Slovakia, Czech Republic, and Ethiopia.
Like fingerprints, each opal is totally unique! To get a really good look at the opals in these designs, click on the images below for a larger view.
An 18k rose gold bracelet featuring rose cut fire opals and brilliant cut white round diamonds.
Tourmaline
Since tourmaline is available in a wide variety of colors, it is ideally suited to almost anyone’s taste. It is known for displaying several colors in the same gemstone. These bi-color or tri-color gems are formed in many combinations; the gemstones with clear color distinctions are highly prized.
One multi-color variety is known as watermelon tourmaline and features green, pink, and white colors bands. To resemble its namesake, the gemstone is cut into thin slices having a pink center, white ring, and green edge.
Tourmaline is found in many localities including Brazil, Afghanistan, East Africa, and the USA.
The following designs feature the varying hues of this October birthstone. Click on the images to see a larger view.
