How To Buy A Gem and Gem Care…

It’s reasonable to expect lasting value and enjoyment when you purchase gemstone jewelry. Learning a few things about gemstone quality and value will help you make sure you get what you want – and deserve.

You can start by trusting your instincts. The sensory appeal is always paramount. So, if a particular gem or jewelry design “speaks” to you, by all means, listen!

You can also use what you know about the 4Cs. The familiar diamond value factors of color, cut, clarity, and carat weight apply to colored gems as well. However, each gem variety is judged by its own potential: no one expects an aquamarine to have the same color as sapphire or emerald to be as flawless as an aquamarine. But there are a few general rules you can use to judge gemstone quality.


Every gem has a unique range of colors. Generally speaking, the purest and most vivid color a gem can have will also be the most expensive. But to really explain gem color, we need to look at the three factors that define any color.

The first is hue, which is what we normally regard as color: for example, a gem’s hue will be red, orange, yellow, green, blue, or purple, or it might be in-between two hues: an orangey-red or a reddish-orange. For most gem varieties, a pure hue is most favored. Gems with a pure red, blue, or green hue are generally the most favored of all.

The second factor is saturation, the intensity of the color. This is the tricky one to picture. Colors that lack intensity often appears faded or washed out or look as though the hue is mixed with gray or brown. A fire engine red is highly saturated, a brick red less so. In gemstone color, more saturation is always better.


The third factor is tone, the lightness or darkness of the color. Pink has a light tone and the maroon has a dark tone. In gems, a medium tone, not too light but not too dark, is considered best. Too light, and a gem’s color is too pale to be attractive. Too dark, and a gem isn’t able to sparkle with light.

A gem’s color is evaluated for hue, saturation, and tone. For example, the best rubies have a vivid pure red color in a medium tone, with no modifying purple, orange, or brown.

But each gem variety is judged on its own terms. For example, aquamarine always has a fairly light tone but its lightness is part of its watery appeal. Gems like orange-pink Padparadscha sapphire or blue-green Paraiba tourmaline are so beautiful, they make gem dealers forget that pure hues are supposed to be better than mixed ones. These gems sell for premium prices simply because almost everyone finds them beautiful. So feel free to follow your own taste.


Next to color, the cut is the most important factor in beauty. Faceted gemstones should have a pleasing shape with a lively display of color and light. The flashes of brilliance a beautiful gem displays are thanks to the skill of the cutter, who selects just the right orientation and angles and proportions to maximize a gem’s appeal.

How can you tell if a gem is well cut? First, it should display brilliance and scintillation evenly across the face of the gem. Unlike diamonds, there is no “ideal” set of proportions for cut: since each variety is different optically, it requires different angles and ratios to look its best.

Move the gem around and see how it handles light. There shouldn’t be any dark lifeless areas or flat washed out zones: light should be reflected consistently back to the eye. Poorly cut gems may have a window: a non-sparkling area in the center where the light just shines through the back instead of being reflected back to dazzle your eye. You’ll find that close observation will reveal whether a gem dance with light or just sits there.

Colored gemstones have much more variety in cuts and shapes available than ever before. Standard ovals, rounds, cushions, trillions, emerald cuts, princess cuts, pears, and marquise shapes have been joined by even more options, traditional and new. Opals, chalcedony, cat’s-eye, star sapphires, laps, coral, turquoise, and other gems with rich deep color are often cut in the smooth dome shape called the cabochon, the favorite shape of the ancient world, which emphasizes color over brilliance.

In addition to standard shapes, the work of today’s innovative lapidary artists also adds unique possibilities to one of a kind jewelry with unusual new shapes and faceting styles.


All-natural gemstones have characteristic inclusions that form along with the gem in the earth. These inclusions may be crystals, needles, voids, fissures, or even tiny pockets of liquid trapped inside. If they don’t detract from appearance, clarity features are accepted in most colored gems and don’t affect value. In fact, they provide a benefit by proving that the gem is natural.


Still, the ideal for most gems is that there should be no inclusions readily visible with the naked eye, particularly if the gem has a light color. There are some gemstones that are extremely rare without visible inclusions. You should expect to see inclusions in emerald, red tourmaline, and, to a lesser extent, ruby.

Carat Weight

Most colored gems are available in a wide range of sizes, but for some the selection is limited. Gems are generally sold by weight, using the carat, which is one-fifth of a gram. Some gem varieties are denser than others: a one-carat emerald will be noticeably larger in size than a one-carat sapphire or ruby. In general, the larger the gem, the more expensive it will be per carat.

For the classic gems like ruby, emerald, and sapphire, prices per carat can increase dramatically as sizes increase. For example, since large ruby is very rare, a three-carat ruby might be three times the price per carat of a one-carat ruby or nine times the total price.


Some gems are much more available in large sizes so the price doesn’t rise as much as the size goes up. Amethyst, Citrine, Aquamarine, Tanzanite, and Tourmaline might have similar prices per carat for a one-carat and a ten-carat stone; although the ten-carat stone will, of course, still be ten times the price.


In addition to the 4Cs, gem values are influenced by natural rarity and the economics of supply and demand. This explains why gems that look similar in color and size can differ substantially in price.

Both sides of the equation of supply and demand come into play. Alexandrite, rare but in demand from collectors, may cost as much as better-known gems. Some gems are relatively rare but since they aren’t well known, there is little demand, keeping prices low. The ancient world couldn’t tell ruby and spinel apart, but spinel’s role as an unknown understudy keeps its price relatively low today even though a one-carat red spinel is rarer than a one-carat ruby. Other rare gems that are relatively affordable include tsavorite garnet, morganite, red beryl, and zircon.

Within each gem variety, quality determines the cost. But different gem varieties have different pricing structures. In general, classic ruby, blue sapphire, and emerald are the most expensive gemstones. One level below these is the rare collector’s gems like alexandrite, demantoid garnet, Paraiba tourmaline, black opal, pink topaz, jadeite, chrysoberyl cat’s eye, fancy sapphire, and South Sea cultured pearls. The moderate price range includes tanzanite, tsavorite garnet, tourmaline, red spinel, aquamarine, precious topaz, spessartite garnet, and Tahitian cultured pearls. Affordable gemstones include amethyst, citrine, spinel, many colors of garnet, blue topaz, chrome diopside, fire opal, white opal, iolite, kunzite, peridot, coral, turquoise, lapis lazuli, chalcedony, and freshwater and saltwater cultured pearls.

The Perfect Setting

The creativity and craftsmanship that go into fashioning gems and making jewelry also affect the value of the finished product. Besides being beautiful, an exquisite gem reflects the union of aesthetics, science, and technical mastery. Fine jewelry combines gems and precious metal with talented design, skilled execution, and attention to even the smallest details.

Value isn’t a deep or complex mystery. However, it simply makes sense to have the guidance of a professional you trust when you purchase your colored gemstone jewelry.


Jewelry retailers who are AGTA members are gemstone professionals who can show you how to judge a gemstone’s quality. Their stores carry a wide selection of classic and unusual gemstones. They have the knowledge and training to give you good advice about choosing gems and pearls, with full disclosure of all the facts that are needed to make an educated and satisfying purchase decision. Just as important, they’re passionate about sharing the beauty and wonder of natural colored gemstones and cultured pearls. Use our retailer finder to find an AGTA retailer near you.


Gems Speak the Language of Love

There is nothing more romantic than expressing your love. When words are not enough, you can use the eloquent symbolism of gemstones to convey what is in your heart. For thousands of years, gems have been lasting testaments to enduring emotions. And their natural beauty gives almost as much daily pleasure as the memory of the moment they were given.


So how to translate the language of gems? The meaning of each gem variety is based on a long tradition, which assigned magical powers to each of these dazzling treasures.

Sapphire, the gem of the soul, represents loyalty, sincerity, and faithfulness: it is a pledge to be true. Ruby expresses a passion that burns as hot as its vivid red hue. Emerald symbolizes rebirth and new life: It can symbolize a new baby, a new beginning, a second chance, the flowering of a heart in bloom.

Because aquamarine was long thought to have the power to soothe troubled relationships as well as to calm rough oceans, today it symbolizes the calm seas and serene depths of a happy marriage.

Amethyst symbolizes peace and sobriety, the perfect reminder to take life one day at a time. Opal symbolizes hope: it is a symbol of your faith that things will work out. Topaz, symbolizing the sun, tells someone that she lights up your life. Because tourmaline symbolizes artistic inspiration, it is the perfect tribute to your muse. A gift of turquoise means forget-me-not.

Pearls were thought to be the solidified tears of Venus, with the power to ensure a bride’s happiness. Symbols of purity and faith, they are a traditional gift for a bride or for the first communion.

In addition to the romantic message hidden in the gift of a gem, people long believed that gems had powers to win love, ward off misfortune, and charm friends and enemies. A gift of a gem may no longer be believed to have the power to inspire devotion. But, let’s face it: it definitely doesn’t hurt!


Gem Care

Gems are among the most durable of nature’s creations. With a little care, they will be
as beautiful for generations to come as they are today.

To keep your gems sparkling, clean them when dust and fingerprints have dimmed their brilliance. The best way to clean your gemstone jewelry is in a bowl of water with a few drops of ordinary dish detergent. Using an old toothbrush or other soft brush, scrub gently behind the stone where dust and soap can collect. Then just rinse and pat try with a soft cloth.


A home ultrasonic cleaner should be used with extreme caution. It can be used to clean ruby, sapphire, diamond, iolite, amethyst, citrine, garnets, iolite, chrysoberyl, and unadorned gold jewelry but it may damage gems like emerald, pink tourmaline, peridot, pearls, coral, lapis lazuli, malachite, turquoise, and any gem that has many inclusions. When in doubt, don’t use it.

Organic gems like pearls, amber, and coral require special care because they are porous. Make sure you don’t expose them to the chemicals in hair products, fragrances, and cosmetics. Store them in a cloth-lined box or pouch and keep them away from other jewelry, which might scratch them. To clean them, simply wipe clean with a soft cloth. Strands of pearls should be restrung if the cord frays or stretches so that individual pearls move.

To keep your gemstone rings looking brilliant, remove them before vigorous exercise or working with your hands. Some gem varieties might be damaged with a sharp blow. When removing your rings, don’t pull them off by the gemstone: this won’t damage the gem but it can, over time, stretch the metal that holds it in place, making the setting less secure.

To protect the beauty of your gems and jewelry, make sure you store each piece separately. Gems may scratch each other or the metal in your jewelry. Avoid creating a tangle of jewelry by wrapping each piece individually or keeping it in its own compartment. Especially when you travel, make sure your jewelry pieces don’t jostle each other in one bag.

If you have jewelry, perhaps passed down to you, that has seen better days or doesn’t suit your style, consider resetting the gems into a modern piece. Gems should be worn and enjoyed, not kept locked away in a safety deposit box.

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