Fascinating Phenomena in Gemstones

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.

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.

 

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.

 

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.

 

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.

 

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.

 

Are you ready to see some of these displays in person? Visit an American Gem Society (AGS) jeweler near you and ask to see some gemstones that exhibit optical phenomena!

Color Comes Into Play with October’s Birthstones

Opal-Tourmaline2

Opal and tourmaline from Gem 2000.

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.

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.

 

If you are shopping for opal or tourmaline jewelry, click here to search for an American Gem Society (AGS) credentialed jeweler near you.

 

Corundum of Many Colors: Sapphire

As we turn our calendars to September, we start thinking of things like heading back to school, sipping on a pumpkin spice latte, and planning our fall fashions. For those celebrating a birthday in September, they’re thinking of their birthstone: sapphire!

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 would then be classified as ruby.

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.

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 make stunning gifts for anyone born in September or celebrating a 5th or 45th wedding anniversary, so be sure to visit an AGS jeweler. They will help you find that perfect gift, whether you’re seeking the classic blue or another shade from the sapphire rainbow.

Need some inspiration? View this collection of designs featuring the sapphire!

Living Coral: Pantone’s 2019 Color of the Year

By Isabelle Corvin, CG, Staff Gemologist at Panowicz Jewelers.

pantone-livingcoralPantone has officially announced it’s 2019 Color of the Year as “Living Coral” (16-1546)!

This bold, energetic, and dynamic color is sure to liven things up for the New Year! Pantone calls Living Coral “sociable and spirited” and says that it is a nurturing color. It’s a blended hue of orange and pink, creating a bright spot in our everyday lives.

The first known written use of the word “coral” to describe a color was in 1513, and the use of “coral pink” was in 1892. The term “coral” for color has been used to described reds, oranges, and pinks, as well as mixed colors from those components.

Cheerful and shocking, coral lends itself well to all aspects of décor, graphic design, and fashion. In fact, you’ll find several gemstones that display this bright, bold, and beautiful color!

Padparadscha sapphire and Rhodochrosite match Living Coral almost perfectly, with their lively blend of just the right amount of pink and orange.

 

Padparadscha is a high-energy stone with an exotic look. The name comes from the Sanskrit word for “lotus.” And indeed, some lotus blossoms exhibit Living Coral excellently!

Rhodochrosite embodies the feeling of Living Coral with its color and the belief that it is a powerful stone for opening your heart once more. It is said to heal emotional wounds and be a guide for finding love.

Other gemstones that depict shades of Living Coral are additional sapphire colors, and some hues of topaz and spinel, as well as certain garnets.

 

Living Coral reminds us that the world around us is alive, filled with wonder and magic, if we only take a few moments to look. The color dives deep into our hearts, beckoning an appreciation for life’s moments and worthwhile memories.

According to Pantone, they chose this color for that very reason. In a world so immersed in technology, we all seek connections. Living Coral is a delight to the eyes and a light to the heart.

Happy New Year!

Jewelry images by credentialed AGS members. Visit ags.org/findajeweler to find an AGS jeweler near you.

isabelle

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.

Choose it for Love. Buy it From a Titleholder.

By Alethea Inns, CGA,
Director of Gemology and Education, American Gem Society

Buying jewelry can be intimidating—it’s a bit like buying a home. It’s a big purchase and you need help from qualified professionals—that you trust—to close the deal. And it’s an emotional purchase; it can represent a big life change.

This is experience talking. I recently bought my first house. It was scary. How was I supposed to spend so much money on something that was so unknown? I had the comps, knew the area, knew the specs of the house and all the data and statistics. But that wasn’t enough. How did I know if there weren’t issues that I couldn’t see? What if the foundation was cracked, or there was mold behind the walls? What if there was a weird smell no one knew the cause of?

That’s why I brought in the experts. I had an amazing real estate agent who knew the area and even researched the owners. I had an appraiser that was ethical who refused to raise the appraised value of the house beyond what he thought was fair. I had an inspector who I trusted to come in and point out every little issue that could be a problem later on.

These professionals were people that I trusted. I knew they had their professional credentials and licenses. They were experts in their fields and most importantly, upheld standards of practice.

This is the exact same reason why you need an American Gem Society (AGS) jeweler when making a jewelry purchase.

AGSTitles

These jewelers are AGS titleholders, which means they are professionals who have pre-requisite gemological or jewelry industry education, verified by the AGS, and then tested by the AGS in their proficiency to grade diamonds. Not only that, they are required to write a Recertification Exam every year to ensure they are up-to-date on the most recent developments in the jewelry industry. If they do not take the annual exam, they cannot maintain their title.

More than being knowledgeable, AGS titleholders are also required to sign an ethics agreement every year and are required to uphold the AGS standards for protecting you, the customer, every day, and in every interaction.

Why shop with an AGS jeweler?

For the same reason you see a certified professional accountant (CPA) to do your taxes, or a doctor that not only has a medical degree, but has their board certification, or the reason you rely on experts with any major purchase, investment, or life event.

An AGS jeweler is there to protect you, their customer. They are there to give you the information you need to make an informed buying decision. Yes, they are there to sell you jewelry, but more than that, they are there to share their passion for jewelry and help you celebrate the moments and reason you walked into their store in the first place.

Ask your jeweler, “Are you an AGS jeweler?” If not, find one that is.

As a credentialed gemologist, Alethea has some favorite gemstones, although it’s not easy to narrow the list down to just a few. Click below to get a closer look at these beautiful gems!

Quote-worthy Jewelry

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!

paula Crevoshay

Opal brooch from Paula Crevoshay.

 

Spinel pendant from Sharon Wei Designs

Pink tourmaline pendant from Sharon Wei Designs.

 

cathy.png

Moonstone, sapphire, and diamond ring from Omi Privé.

 

lindsay.png

Custom-designed ring from Michaels Jewelers.

 

alexis.png

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.

Setting our Sights on Sapphires

By Robin Skibicki

As we change our calendars to September, our sights are set on cooler weather, and on sapphires!

Sapphires are known for their beautiful blue hue, but they can also be found in a variety of pinks, yellows, and oranges, even peach, green, and violet colors. These colors are referred to as fancy sapphire.

One of the most sought-after fancy sapphires is the padparadscha. Its pink-orange coloration can be compared to that of a tropical sunset. Princess Eugenie, a cousin to Princes William and Harry, received an oval cut padparadscha sapphire ring for her engagement, bringing this rare gemstone into the limelight.

Omi-sapphire

Padparadscha sapphire and diamond ring by Omi Privé. This ring is the AGTA 2018 Spectrum Award Winner.

Sapphires can also display the celestial-like optical phenomena, asterism, adding the name “star” to this type of sapphire.

Suna-PinkStarSapphire-loose

Pink star sapphire cut en cabochon, by Suna Bros.

September babies are lucky to have a birthstone that comes in a variety of colors! Below are a few images from American Gem Society (AGS) members that showcase the chromatically-gifted sapphire. To find an AGS-credentialed jeweler near you, click here!