A guide to the essential traits of natural gems.
Chances are you’re passionate about natural gems. Emerald’s lush, vivid green. Ruby’s fiery crimson. Blue sapphire’s deep blue glow or alexandrite‘s chameleon effect. Pearl’s shimmering glow. Your admiration for these and other elegant gems probably attracted you to the jewelry profession. It might also have led you to enroll in Colored Stone Essentials.
The formal definition of colored stone is any gem that isn’t a diamond. But leaving it at that says far too little. A colored stone transforms nature’s allure into a single glinting object of desire. These timeless jewels capture all the colors the human eye can see—lilac, azure, magenta, saffron, teal, scarlet, and more.
For centuries, artists and poets have used the powerful images of colored stones to express love, passion, and power. At the same time, people from all walks of life adorned themselves with the dramatic, radiant grace of colored stone jewelry.
The subtle magic of gems reveals itself in a tanzanite necklace draped around a woman’s neck or a sapphire bracelet glistening on her wrist. But charm isn’t easy to explain, and buying colored gemstones for your jewelry rarely does themselves by magic alone.
The Nature of Natural Gemstones
- What three traits do all gems share?
- Why is color the most crucial factor in a colored stone’s visual appeal?
- How does consumer demand affect a gem’s value?
Two thousand years ago, students of gemology classified gems by color alone. For example, they would have considered ruby and red spinel the same thing simply because they’re the same color. But there is a tremendous difference between the two gems, which you’ll become more aware of as you progress through this course.
Some gems—like pearls, amber, coral, and ivory—are organic, which means they come from plants or animals. But most gems are minerals: natural, inorganic materials with specific chemical compositions. Most have a characteristic structure, too. You probably already know the names of some minerals commonly found in jewelry stores: topaz, sapphire, emerald, and ruby, for example.
Three Traits of All Natural Gems
A substance isn’t automatically considered a gem just because it’s used in jewelry or just because it falls in the mineral category. Items like bones, seeds, and hair have all been used in jewelry, but that doesn’t place them in the same category as rubies, pearls, and amber.
To be a gem, a substance must share three essential traits with all other gems: beauty, rarity, and durability. Each quality represents a range so that all gems can possess different levels of all three traits.
Beauty
Humans have cherished the color and sparkle of finished gems throughout the centuries. Mineral crystals brought up from the earth’s dark depths, organic gems created by life processes—all gems worthy of the name share the virtue of beauty.
But because beauty is in the eye of the beholder, it can be challenging to categorize what’s beautiful and what isn’t. One accepted definition of beauty holds that it’s a combination of qualities that delight the senses or appeal to the mind. In other words, a thing of beauty might not cause everybody to react the same way, but it will cause everybody to respond—it will have visual appeal.
In fashioned gemstones, visual appeal typically results from color, symmetry, and surface appearance. Of these factors, color is usually the most important for colored stones. From the deep green of a fine emerald to the shifting colors in an opal, color is the first thing you notice about a colored stone. For this reason, it’s usually the first consideration when selling colored gemstones.
Symmetry, the second factor, means balance and harmony of cut. A stone is most appealing when its shape and proportions are balanced, so certain cut details enhance a gem’s beauty.
Rarity
Rarity, too, is a sliding scale, meaning some gems are rarer than others. A few are so rare that they’re considered collector’s items. Gem-quality benitoite and red beryl—found in only one place on earth—are occasionally used in jewelry. Because they’re not nearly as available as gems like sapphire and amethyst, they’re unknown to most consumers. Most gemstones are somewhere in the middle of the rarity scale.
Rarity doesn’t always make a gem valuable. Pink spinel, for example, is lovely, durable, and rare. Despite its virtues, pink spinel is generally absent from consumer shopping lists. Few people know about it, so there’s little demand for it.
Demand is unpredictable. Amber, highly treasured in centuries past, is less prized today, although rare specimens can still command high prices. Similarly, jet—an opaque black organic gemstone—was extremely popular in Victorian England but is virtually unheard of in jewelry today.
Often shrewd marketing can sway consumer preference. Suppose a significant retailer backs a gem with an expensive advertising campaign. In that case, it’s more likely to penetrate the market quickly, as was the case with tanzanite, the striking violet-blue East African gem. But no matter how energetically it’s marketed, natural gems must be beautiful, durable, and rare to merit popular success. And it must be available in sufficient quantities to stay in the public consciousness over the long haul.
Durability
Autumn leaves are lovely, with their rich, mottled wine reds, golden yellows, and graceful, symmetrical shapes. But, a child who puts a scarlet leaf on a string to wear around her neck will soon find it brown and shriveled. Leaves, unlike gems, lack durability. Leaves fade, change shape, and decay. Gems endure.
Durability combines three factors: hardness, toughness, and stability.
Hardness measures how well a gemstone resists scratching and abrasion. Toughness is the ability to withstand breaking, chipping, and cracking.
Hardness and toughness are not the same thing. Topaz is a relatively hard stone, but it has poor toughness. Jadeite is not as hard as Topaz, but it has exceptional toughness.
Stability measures how well a gemstone resists the effects of light, heat, and chemicals. For example, the cleaning solutions that make sapphires sparkle can damage peridot. Likewise, everyday sunlight can fade kunzite over time.
Low durability is why we can not usually use beautiful minerals like fluorite and calcite in jewelry. Of course, we can polish those minerals, and most agree that both are beautiful. But they have very low hardness and poor toughness, so we rarely use them in jewelry.
Buying the Best Natural Gems
When you decide to invest in a natural gem, determine a budget you can afford. Then you have to do your research on what it is for. For example, an everyday ring, a unique occasion jewelry, or add to your collection. The type of gemstone you want to purchase would be different depending on that. Sapphires and rubies are perfect in hardness and stability and can wear every day yet have the luxury for any special occasion too. Do your research on how to identify the best sapphires.