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!

Four Holiday Shopping Tips

Trying on ring at jewelry store

Tips on Buying Jewelry This Holiday Season

With the holiday shopping season here, the American Gem Society (AGS) has been receiving questions from shoppers seeking jewelry buying tips and secrets. We thought we would answer a few of our most frequently asked questions to help ease the pressure off this hectic season.

“How do I know if I’m getting a good deal?”

Trust your jeweler. Do your research, read reviews of their store, ask friends and shop with a credentialed jeweler. We take great efforts to vet all of our members, to make sure that they continue their gemological education and that they adhere to the AGS standards of ethics and integrity.

Click here to learn more about the importance of shopping with a credentialed AGS jeweler.

To find an AGS member jeweler near you, visit americangemsociety.org/findajeweler.

“Before I buy gems that have been altered to enhance their appearance, is there anything I need to know?”

Make sure that the piece comes with the proper disclosures and that you understand how to care for the gemstones. Ask your jeweler if the treatments are permanent. For example, fracture-filled diamonds can have their filling damaged by an ultrasonic cleaner or steam cleaning. Some irradiated stones are susceptible to color change with high heats such as that from a jeweler’s torch.

“What advice do you have when shopping for diamonds?”

Ask for a diamond that comes with an independent diamond grading report, specifically, an AGS Laboratories diamond grading report. AGS Laboratories is a nonprofit lab created with a mission of consumer protection.

A diamond grading report from AGS Laboratories offers a simple, straightforward, and intuitive 0-10 scale and provides all the information you need to be comfortable with your diamond-buying decision.  Visit americangemsociety.org/agsdiamondgrading to learn more.

“When should I get an appraisal?” 

There are different kinds of appraisals for different purposes. The most common reason for an appraisal is to obtain insurance to ensure a replacement of equal quality and value in the event of damage or loss.

For this purpose, either an Insurance Replacement Appraisal or Statement of Replacement Cost should be requested. The Insurance Replacement Appraisal represents the retail replacement cost with a comparable item.

The Statement of Replacement Cost is provided by the actual seller of the item of jewelry and will report the actual selling price based on the normal selling price of that item in that particular store. In general, you want to get your appraisal updated every two years, or if you have a significant life change, like a change of address. Of course, the best reason to get an appraisal is if the piece has significant meaning to you.

To find an AGS-credentialed appraiser near you, visit americangemsociety.org/findanappraiser.

If you have more questions, you can reach out to any AGS member jeweler or AGS-credentialed appraiser, and they’ll be happy to assist you. The American Gem Society wishes you a very happy holiday season, full of sparkle and wonderful surprises!

What’s That Bracelet (REALLY) Worth?

By David Craig Rotenberg, ECGA (AGS), GG (GIA), CSM (NAJA), CAPP (ISA)

 

Gold Jewelry  With Gems , Chains Close Up Macro Shot Isolated OnJewelry appraisals are important documents that are required for insurance valuations, the settling of an estate, determining the value for tax deductions for charitable contributions, for casualty loss evaluations, or perhaps the division of property in a divorce.

The appraisal is simply a means of factually communicating what a piece of jewelry is worth. It’s the item’s value assessed by quantitative and qualitative aspects as determined by a skilled professional appraiser. This individual should not only understand the science of valuation, but should be able to properly communicate the background on exactly how he or she arrived at that assessment.

Insurance Appraisals

Insurance appraisals are used by insurance companies to determine exactly what cost is required to replace an exact piece of jewelry in the current climate in the event of theft or loss. The appraiser provides a full evaluation of the item, including a detailed description of quality and special nuances of the item. While each insurance company may operate differently, most won’t simply accept purchase receipts since the determined “value” is the key when writing a policy or reimbursing a claim.

Appraisal

Settlement Appraisals

It is especially important to have an experienced appraiser when appraising for tax purposes. When someone dies, jewelry must be categorized to determine fair market value in regards to inheritance tax as applied by the IRS. Fair market value is a different determination than replacement value, which you obtain for insurance purposes. In terms of a divorce, an appraisal might be required to help determine equitable distribution of property. Jewelry is part of the “estate” and needs to be categorized for tax purposes.

The Process

After you contact a jewelry appraiser, they will sit down with you and review the items you want to be appraised. The condition of an item is extremely important; a broken watch from the 1960s, for instance, might be valued like a typical flea market item while a vintage Rolex in great condition from the same time period would be appraised at what it would bring on the second-hand market. Diamond rings normally have laboratory reports evaluating their quality. New jewelry that is being appraised for insurance purposes should be accompanied by receipts from the store where purchased so the appraiser can refer back to the original jeweler if there are questions.

 

Finding a Qualified Jewelry Appraiser

You can contact the American Gem Society (AGS) for a list of certified appraisers in your area. Certification by the AGS indicates that the individual is not only a certified appraiser, but also an expert gemologist. The AGS is one of the oldest nonprofits dedicated to consumer protection in the industry. A certification will usually be displayed in the appraiser’s workspace—this certificate required a lot of time and effort and the appraiser will want to show it off!

Other reputable organizations include the National Association of Jewelry Appraisers (NAJA) and the American Society of Appraisers (ASA). Some people ask if it’s necessary to obtain two appraisals; in most cases, this shouldn’t be necessary, especially if you’re confident you’ve gone to a qualified appraiser.

Over the Years

Before the 1980s, there wasn’t a lot of formal appraisal education and a jeweler might simply assess an item for what they might sell it for in their own showcase. The average jeweler didn’t have a lot of resources—an item might be sold based on what someone told them it was worth.

With the founding of the International Society of Appraisers (ISA) in 1979, appraisal education became more of a studied science. As gemology education blossomed, jewelers were able to conduct research, compile pricing information and attend continuing education as they used their new-found gemological skills for buying and appraisal purposes. Transparency is critical—an appraiser must be able to thoroughly explain how they arrived at a value.

ABOUT THE AUTHOR:

DRotenbergDavid Craig Rotenberg is an AGS-certified gemologist appraiser and one of a handful of CAPP (Certified Appraiser of Personal Property) appraisers in gemstones, contemporary jewelry and antique and period jewelry. He is a member of the Jeweler’s Vigilance Committee Appraisal Bar, has studied with the American Arbitration Association, and is past president of the AGS’s Jewelers Education Foundation, founder and past president of the Delaware Valley Keystone Guild and founder and past president of the Delaware Valley chapter of the International Society of Appraisers. Recognized by the Technical Advisory Service for Attorneys (TASA) for his expertise, he is part of the Jeweler’s Vigilance Committee’s appraisal organization and has conducted jewelry appraisals for the U.S. Treasury Department. Most recently, he completed a global leadership program at Harvard University School of Business.

In addition to offering his appraisal services to customers at David Craig Jewelers in Langhorne, PA, David has appraised multi-million dollar inventories for the federal government and many banks. He has conducted evaluations for a large variety of complex estate and bankruptcy matters and fraud investigations. He also operates an AGS-accredited gem lab at David Craig Jewelers.

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.

Celebrate the Woman Who Means Everything

By Robin Skibicki

“Being a mother is about learning about strengths you didn’t know you had and dealing with fears you didn’t know existed.” – Linda Wooten, author.

When I was 9 years old, I asked my Mom on Mother’s Day why there isn’t a Children’s Day. Without hesitation, she responded in a kind but firm voice, “Honey, EVERY DAY is Children’s Day.” I knew that tone and I also detected that wasn’t the best question to ask at that moment.

Now that I’m a mom, I get it! In fact, I believe mothers truly need more than one day a year to call their own. How about once a month? The list of gratitude towards our mothers can be infinite, from the little things, like kissing a “boo-boo,” to jumping in with all her heart and soul to help us through a rough situation.

Nowadays, we realize that Mother’s Day isn’t just about mothers. The holiday extends to celebrate all the incredible women who have made significant contributions in our lives, helping us become who we are today. She can be a stepmom, mother-in-law, grandmother, daughter, daughter-in-law, aunt, sister, cousin, friend, teacher, or mentor.

If you are looking for a gift that is beyond special and significant for a fabulous female in your life, consider fine jewelry. They’re not only gifts that will make her smile (possibly with a glistening tear in her eye) once she opens it, but each day she wears it. She will treasure it for years to come and it will ultimately become a cherished heirloom.

The credentialed members of the American Gem Society (AGS) have got you covered for Mother’s Day. Here are a few ideas to get you started. If there is a design you like or have an idea of your own, contact an AGS jeweler near you!