Six Displays of Optical Phenomena in Gemstones

By Robin Skibicki

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.

 

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.

 

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.

 

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.

 

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!

August’s Trio of Distinctive Gemstones

It’s been a year since spinel was added to August’s birthstone line up. Those celebrating a birthday during the eighth calendar month now have three gemstone choices: peridot, sardonyx, and spinel.

Spinel

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Blue spinel by Gem 2000.

For those who are still unfamiliar with spinel, it is often assumed to be other gemstones, like ruby or sapphire.  Cobalt blue, like the one above, is one of the most desired colors. But it can be found in a variety of colors, such as the much coveted red, as well as black, violet blue, greenish blue, grayish, pale pink, mauve, yellow or brown. Spinel can also be found in various cuts, like octagons, trillions, squares, rounds and fancy shapes, like ovals, pears, and cushions.

No matter what the shape, spinel is spectacular! Take a look at these designs by our AGS members. Click on the images for a closer view.

 

Peridot

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Peridot by Gem 2000.

The verdant peridot is the gemstone most commonly associated with August. Peridot’s recognizable green hue could sometimes vary from yellowish-green to olive to brownish green, contingent on how much iron is present. Yet the finest peridot is a brilliant green without any hints of brown or yellow.

Our AGS members will help you find the perfect peridot for you! Click on the images for a closer view.

 

Sardonyx

Sardonyx

Since as far back as Roman times, sardonyx has been highly valued as a stone representing strength, courage, happiness, and clear communication.

The unique reddish, zebra-striped banding of sardonyx stands out beautifully when the stone is smoothed, so it is often cut in cabochon and worn as beads or featured in an eye-catching pendant or ring.

Sardonyx makes a great gift for those born in August who want something a little different than the traditional birthstone. Readily available and relatively inexpensive, sardonyx makes an affordable addition to anyone’s collection.

If you’d like to add spinel, peridot, or sardonyx to your jewelry wardrobe, contact a credentialed AGS jeweler near you!

Silver Shines On

By Robin Skibicki

The popularity of silver jewelry never seems to ebb, as designers are finding new and artistic ways to style the affordable and malleable metal. Whether silver is mixed with other metals or set with diamonds and gemstones, it’s a go-to look that complements a wide range of colors and styles.

For centuries, silver has been prized for its incredible luster and workability. In this industry, we naturally think of it as a versatile metal used to design beautiful jewelry. But it’s also applied towards technology and industry, used in the home, and often considered for investment purposes.

Pure silver is highly tarnish-resistant but is too soft to use for jewelry design. Other metals like copper, nickel, or zinc, are added to harden silver. For example, sterling silver is 92.5% silver and 7.5% another metal. Silver products sometimes may be marked “925” which means that 925 parts per thousand are pure silver.

Some jewelry may be described as silverplate: a layer of silver is bonded to a base metal. According to the law, quality-marked silver also must bear the name or a U.S. registered trademark of the company or person that will stand behind the mark.

If you’re looking for an inexpensive metal for your fine jewelry, silver is a good choice. Since silver is soft and scratches easily, it’s best used for jewelry that is not worn daily.

The versatile beauty of silver is showcased in these designs by our credentialed AGS members.

Michael Schofield & Co.

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A twin fish motif artfully decorates a sterling silver cuff.

 

Breuning

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Petals of silver and silver coated with yellow gold feature a sapphire center.

 

MK Diamonds & Jewelry

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Sterling silver earrings featuring pear-cut blue topaz and blue sapphires set in black rhodium sterling silver.

 

Parlé

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Sterling silver Australian boulder opal and sapphire pendant.

 

Ed Levin Jewelry

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Sterling silver Secret Heart Bracelet “swings open” to reveal a secret heart.

If you’re in the market for silver jewelry—perhaps you like one of the designs pictured above—or have some silver jewelry that needs some TLC, visit a credentialed AGS jeweler near you.

The 2017 Pantone Color of the Year is…

By Isabelle Corvin, CG, Staff Gemologist at Panowicz Jewelers

Greenery!

It has been some time since a green hue has been chosen as the color of the year, and this version—a bright shade with just a hint of yellow—is a refreshing color indeed!

pantone-greeneryPantone says it was chosen as a symbolic color of new beginnings and renewal, a calming hue to soothe and relax, and a call to reconnect with the world around us. Indeed, Greenery reminds us of nature, and few things calm like plants and animals.

The color will be coming to the forefront of all things fashionable this year; clothes, interior décor and of course, jewelry.

Gems that embody this color are reviving peridot, versatile tourmaline, vibrant tsavorite garnet and of course, comforting emerald. In fact, emeralds have been a symbol of renewal and growth for ages, as well as wealth and status.

Alternately, peridot is considered the gem of the sun, while garnets and tourmalines have many meanings and supposed health benefits.

Certainly, all gems that match this sublime “Greenery” represent nature at its finest.

The color green, at its scientific core, is a color between blue and yellow, a mixture of those two opposing colors, if you will. The word, “green”, is thought to be derived from Middle English or possibly Germanic roots, most likely meaning, “grass” or “roots.”

In many cultures and languages, green and blue often have similar names associated with the color, making it a great transition from last year’s Pantone color of the year, Serenity (a soft blue).

Science has proven that green is restful on the eyes, balancing to emotions and also helps combat fatigue.

Green is surprisingly hard to “copy” from nature’s mix to create pigments and dyes, including food coloring. Older methods included finely powdered malachite, another gemstone, to create stains.

Historically, green has an interesting history; in more arid locations, the color was one of hope for things to come and rebirth. The Egyptians used the color often, even going so far as to characterize some of their deities with green skin.

The Greeks weren’t overly fond of the color and rarely used it in artistic purists. The Romans, however, linked the color to their goddess, Venus, who was the goddess of love and nature, thus making the color more romantic.

During the Renaissance, where clothing colors denoted social status and occupation, green tones were worn primarily by merchants and bankers. It was a featured clothing color in many famous paintings of the era, including Mona Lisa, who wears a shade of darker, muted green.

The Masonic orders use green to symbolize immortality of all that is divine and true. Since the natural aspect of the color is unchanging, it is considered an immutable color.

In terms of jewelry, green was a popular color in both the Art Nouveau and Art Deco eras. In the former, it was used for accents of sweeping, nature-inspired designs that dominated the movement.

In the latter it was often used as a striking aside to other colors, using the bolder, darker hues of the color rather than the light and airy versions.

Greenery may seem like an odd choice…until the plants bloom once more. As spring hits, sooner rather than later, green becomes the prominent color we see. It is a surprisingly balanced color, managing to be both soft and bold. It is a romantic color, when you think about it, and invokes emotions when seen.

We all need a connection to nature in some form, and Greenery gives us that connection with our most obvious sense, sight.

And when it is seen, it is felt.

To see green colors is to feel them, and to wear a gemstone that holds such a deep tie to the world around us grounds us, makes us feel.

Wearing green jewelry is sure to help you feel at peace throughout your day. Who doesn’t need to feel relaxed during hectic and overfull days?

Embrace a green gemstone, make it your own and begin to enjoy 2017’s color, Greenery!

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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.

Ignite Your Passion for Purple!

Amethyst is a violet variety of crystal quartz. Macro Texture purple crystals.For some, the color purple calms the mind and nerves. It encourages creativity and offers a sense of spirituality. It can signify royalty, virtue and faith, wealth and position, and courage. Purple unites the “wisdom” of blue and the “love” of red. It’s the distinguishable color of February’s birthstone, amethyst, which seems quite apropos for a month often associated with love and passion!

Amethyst is a purple quartz exhibiting a beautiful blend of violet and red that can be found all over the world, including the United States, Canada, Brazil, and Zambia. 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.

While amethyst is most commonly recognized to be a purple color, the gemstone can actually range from a light pinkish violet to a deep purple that leans more towards blue or red, depending on the light. Sometimes, even the same stone can have layers or color variants, so the way the gemstone is cut is important to the way the color shows in a finished piece.

Today, many wearers simply prize the amethyst for its beautiful shade and the way it complements both warm and cool colors. Below you’ll find designs by our AGS members which feature the amazing amethyst. Click on the image to get a closer look.

Have any of these designs ignited your passion for the peaceful purple quartz? If you are in search of fine jewelry featuring amethyst—or if you’d like someone to design a special piece for you—get in contact with a jeweler you can trust. Search for an AGS jeweler near you, https://www.americangemsociety.org/en/find-a-jeweler.

Four Fun Facts About January’s Gemstone

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Rhodolite garnet and emerald sunbeam earrings by Ricardo Basta Fine Jewelry.

If you’re celebrating a birthday or any special occasion this month, then the garnet is a worthy addition to your fine jewelry wardrobe. Here are four fun facts about the colorific January gem:

1. Not all garnets are red.

Garnet is actually 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.

2. It’s more than just a gemstone.

For thousands of years, the garnet has lived a glamorous life as a gemstone. But in the past 150 years, it has also been put to the test as an effective industrial mineral. In the United States, garnet has been utilized for waterjet cutting, abrasive blasting, and filtration.

3. Their inclusions make them unique.

Some garnets have inclusions that are part of the beauty of the overall stone (like “horsetails” in Demantoid garnets, or Hessonite garnets which sometimes have a “turbulent” look). So you may discover that you like the distinctive look these inclusions bring to the piece.

4. Garnets have been around for a very long time.

The garnet is so durable, remnants of garnet jewelry can be found as far back as the Bronze Age. Other references go back to 3100 BC when the Egyptians used garnet as inlays in their jewelry and carvings. The Egyptians even said it was the symbol of life. The garnet was very popular with the Romans in the 3rd and 4th Century.

Today, the garnet can be found in a range of jewelry pieces and styles, from beautiful rings to stunning tiaras. Since the garnet can come in a range of colors, rare garnets in green or blue make breathtaking pieces, especially in pendants or drop earrings.

Here are a few designs from AGS members featuring the many colors of the garnet. Click on the images for a larger view.

To learn more about the wide range of garnet color options and to pick the perfect piece, search for an AGS jeweler near you!

‘Tis the Season for Stackables, Studs, and Solitaires

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The holidays are only a few days away, so if you’re still looking for something super special for the season, the American Gem Society (AGS) suggests stackables, studs, or solitaires. These pieces are always on trend and are regular go-to items in any fine jewelry wardrobe.

Below are some dazzling designs by our AGS members that are sure to inspire. If you need more ideas, you can always count on an AGS jeweler to help. Every year, our AGS members are required to continue their gemological education, staying up-to-date on changes and trends in the jewelry industry. Search for an AGS jeweler near you by clicking here.

Stackables

The beauty of a stackable bracelet or ring is that you can wear them individually, mix and match to change the look or wear them all together. So many options!

Studs

These days, when it comes to studs, the possibilities are endless! You could sport a solitaire diamond or gemstone by day, and then dress it up with an earring jacket by night.

Solitaires

Often a solitaire is presumed to be a round diamond, simply set as a ring or pendant. But today you’ll find these singular stones come in all shapes, sizes, and species—like corundum (ruby and sapphire) and quartz (amethyst and citrine).

Always keep in mind, when purchasing a diamond—whether it’s a loose stone or mounted—to ask your jeweler for an AGS Laboratories Diamond Grading Report. That way you can be confident that your diamond has been consistently and accurately graded by the only nonprofit diamond grading laboratory with the mission of consumer protection. Accept no substitutes. Happy shopping!