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!

Four Fine Jewelry Trends for Spring 2019

Spring is here and we’re ready for some jewelry trends to help us celebrate this much-welcome change of season! Now that the weather is warming up, what’s hot? We’ve gathered some season-sensational (We just made that up!) designs from our AGS members.

Quite possibly the most quintessential symbols of spring are flowers, butterflies, and bees. Naturally, their likenesses are found in a variety of fine jewelry designs.

 

Next on the list is chains. Big chains. Little chains. This trend is an ode to the Eighties and they’re everywhere!

 

It’s been said that pearls never go out of style, but these aren’t your grandmother’s pearls! Modern designs have re-imagined the classic jewelry wardrobe staple.

 

The warmer weather has us looking towards the sky and the sea for a much-needed getaway! Both celestial and nautical-themed designs inspire us to seek the outdoors (and beyond) for our next adventure.

 

Are you ready to add a bit of bling to your spring wardrobe? Find an American Gem Society jeweler member near you at www.ags.org/findajeweler.

The Beauty of a Brown Diamond

Did you know that brown diamonds show more flashes of colored light than “colorless” diamonds?

If you are in the market for brown diamonds, be sure to ask your jeweler for an AGS Laboratories Colored Diamond Document. It’s a grading report that presents the technical aspects and nuances of colored diamond grading to jewelry buyers with easy-to-understand verbiage and graphics.

Brown diamonds will no longer be described simply as “a brown diamond,” but will be communicated visually, highlighting the nuances within the diamond’s color. For example, a diamond with even distribution of brown throughout and hints of orange, could be described as a deep, rich, brown diamond with moderate orange accents.

Click the image below to view the Colored Diamond Document.

AGSL-CDD

“Brown diamonds are beautiful and are an alternative choice to the more traditional colorless diamonds. They are also trending as an affordable choice for fine jewelry,” said Jason Quick, Laboratory Director at AGS Laboratories. “We recognized a growing need in the market and decided to create a tool that will truly enhance consumers’ buying experience.”

AGS Laboratories encourages jewelry buyers who are shopping for diamonds to always ask for a diamond grading report from an independent third-party laboratory so that they can better understand the quality of the diamond they are buying. To find an American Gem Society retailer, visit americangemsociety.org/findajeweler.

To learn more about AGS Laboratories Colored Diamond Document, visit agslab.com/browndiamonds.

Here are a few designs we love from members of the American Gem Society that feature brown diamonds.

American Gem Society Members Sparkle in Nashville

The American Gem Society (AGS) Suppliers’ Reception and Showcase occurs annually during the American Gem Society’s Conclave, the industry’s premier educational and networking event.

This year’s Conclave was held in Nashville, TN, and the AGS Suppliers’ Reception and Showcase featured 16 AGS members. Below are photos from the highly successful evening, featuring the incredible jewelry and the lovely ladies who modeled them.

Click on each photo to get a closer look.

 

If there’s a design you like and want to know more, contact an AGS-credentialed jeweler near you.

Get to Know Your Brown Diamond

AGS Laboratories recently unveiled their new Colored Diamond Document, a grading report that presents the technical aspects and nuances of colored diamond grading to jewelry buyers with easy-to-understand verbiage and graphics.

Brown diamonds will no longer be described simply as “a brown diamond,” but will be communicated in an easy-to-understand visual way, highlighting the nuances within the diamond’s color. For example, a diamond with even distribution of brown throughout and hints of orange, could be described as a deep, rich, brown diamond with moderate orange accents.

Click the image below to view the Colored Diamond Document.

AGSL-CDD

“Brown diamonds are beautiful and are an alternative choice to the more traditional colorless diamonds. They are also trending as an affordable choice for fine jewelry,” said Jason Quick, Laboratory Director at AGS Laboratories. “We recognized a growing need in the market and decided to create a tool that will truly enhance consumers’ buying experience.”

AGS Laboratories encourages jewelry buyers who are shopping for diamonds to always ask for a diamond grading report from an independent third-party laboratory so that they can better understand the quality of the diamond they are buying. To find an American Gem Society retailer, visit americangemsociety.org/findajeweler.

To learn more about AGS Laboratories Colored Diamond Document, visit agslab.com/browndiamonds.

Here are a few designs we love from members of the American Gem Society that feature brown diamonds.

It’s Only Natural

By Robin Skibicki

Not all gemstones are minerals with a crystalline structure. In fact, some were formed through biological processes of living organisms, such as plants and animals. These natural beauties are referred to as organic gemstones and include several varieties that are important to the gem trade. We’re talking about pearls, coral, amber, ammolite, and shell, just to name a few.

Pearls

Pearls are pretty much perfect for any occasion. It doesn’t matter if you’re dressed in silks and satins or khakis and jeans, they go with everything! There are several types to choose from, like freshwater or saltwater, natural or cultured, with such varieties as Akoya, Keshi, South Sea, and Tahitian.

 

 

Coral

There are hundreds of species of coral throughout the world, but only a few are used for fine jewelry. Corallium japonicum and Corallium rubrum are two varieties of red coral commonly used to produce jewelry, and Antipatharia, a species of black coral prized for its lustrous, black appearance after polishing.

 

 

Amber

Amber had its moment in the spotlight when it appeared as a source for “Dino DNA” in the movie, Jurassic Park. This fossilized resin of ancient tree sap dates back 25 to 50 million years, with some of the oldest known material dating back 290 to 350 million years ago. Amber comes in over 300 different shades, with the most common colors being honey, green, cherry, cognac, citrine, and butterscotch.

 

 

Ammolite

Ammolite is an iridescent gemstone material that comes from the fossilized shell of extinct squid-like creatures called ammonites. They only come from one place: Alberta, Canada. Although they have been forming for millions of years, ammolite first appeared in jewelry in the 1960s and was recognized in 1981 as an organic gemstone.

 

 

Shell

Shell has been used for decorative purposes for centuries and was most likely the by-product of the search for food. It’s been used for everything from buttons to knife handles, from cameos to necklaces. In jewelry design, the two most familiar types of shell are abalone and mother-of-pearl.

Interesting facts: Abalone is composed of mother-of-pearl. Mother-of-pearl is called nacre, which makes the outer layer of pearls.

 

 

Visit an AGS-credentialed jeweler near you and ask them to show you some organic gemstones!

 

AGS Member Spotlight: ASBA USA, Inc.

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.

 

If you’d like to see more designs by ASBA USA in person, contact a credentialed AGS jeweler near you.