How to select quality gemstones and gemstone jewelry
Beauty. Rarity. Durability. Discover the attributes that attract us to colored gemstones for personal adornment and make gemstones valuable and precious. Colored gemstones provide the opportunity for uniquely personal expression. Use Jewelers of America’s guide to buying gemstone jewelry to ensure you select the highest quality gemstone jewelry for your budget.
How Gemstones Are Graded
While gemstones have similar quality factors as diamonds (cut, clarity, color and cut), they are valued differently for gemstones. For example, color is by far the most important C for colored gemstones, whereas cut is usually considered the most important C for diamonds.
Most colored gemstones derive their beauty from their color – purples, blues, greens, yellows, oranges, reds. Three factors relate to a gemstone’s color:
Hue: the pure color on the spectrum, describes the dominant color and any additional colors visible in a gem.
Tone: the lightness or darkness of a color. In the GIA color-grading system, tones range from very light to very dark.
Saturation or intensity: is the purity of the hue.
When buying colored gemstone jewelry, select what you consider beautiful. Because of the subtle differences in the tone and hue of the colored gemstone you are considering, look at several to find the one you prefer. Each gem variety has an optimal hue, tone and saturation, your jeweler can show you and explain the how gemstones each exhibit their optimal color.
Gem cutters work to achieve a pleasing and affordable mix of color, weight and a safe shape for mounting. During creation, a gemstone’s size is constrained by nature. For example, while large and beautiful amethysts are readily available, an alexandrite of large size is extremely rare.
Sparkle adds to the beauty of a well-cut colored gemstone. The cut of a colored gemstone describes its shape and how it is fashioned. Some gemstones, such as opal, are suited to a smooth, rounded surface. Others, such as sapphire, are more frequently shaped with a precise series of flat, symmetrical planes, called facets, which make the most pleasing illumination of the gem’s color. Some cutters today may also use convex or concave facets, shaping colored gemstone like small sculptures.
The clarity of colored gemstones contributes to their beauty. Unless a gemstone is opaque and blocks all light, how light moves through the gemstone affects its beauty. Some gemstones have few internal inclusions to interrupt the passage of light, as is the case with most pieces of tanzanite. Others have characteristic inclusions. For example, some emerald has a “jardine” (garden), which makes each gem truly unique.
Learn more about Clarity >
Gemstone weight is measured carats. The jewelry industry also measures colored gemstones by dimensions in millimeters in addition to carat weight. Millimeter size is taken into consideration when matching colored gemstones for a ring, earrings or other types of jewelry.
A gemstone’s ability to be fashioned, mounted and worn is a function of how durable it is – a matter of both hardness and toughness. Some gemstones, such as sapphire, ruby and garnet, are well-suited to an active daily life and work well in rings, bracelets or cufflinks. Others, such as emeralds, pearls and opals call for earring or necklace mountings to keep them beautifully displayed but out of harm’s way.
In certain colored gemstones color occurs naturally. Satisfying hues are intrinsic in some garnets, for example. In other colored gemstones, the final color occurs with assistance. For nearly as long as people have worn rubies, we have known how to treat a rough ruby with heat to obtain a desirable red color. Not all rubies are heat treated, but the vast majority are. Because of their rarity, gemstones in which color is naturally occurring are generally more valuable.
Many gemstones are treated or enhanced in some way, such as with heat or safe irradiation, to achieve the beautiful colors or clarity we desire in the sizes we desire. These gems, which are less rare, can also be very valuable. Some jewelers make synthetic colored gemstones available. Synthetic colored gemstones have all the optical, physical and chemical properties of naturally occurring gemstones, but they are created in a laboratory rather than occurring in nature.
Buying Colored Gemstone Jewelry
When selecting colored gemstone consider the following:
- Do you love the color?
- Does the gemstone have brilliance and fire?
- Does the gem have light throughout the stone, or are their flat areas?
Some jewelers offer loose colored gemstones and will help you create a personalized mounting. You may prefer to buy a finished jewelry item. Discuss how you see yourself wearing the piece so that your jeweler can help you select mountings consistent with your lifestyle. This will provide the best safeguard for your purchase.
You have the right to know what you are buying, whether it is a natural gemstone, an enhanced or treated gemstone, or a synthetic gemstone. The Federal Trade Commission (FTC) has established guidelines for the jewelry industry stating that jewelers must disclose any treatment that is not permanent, that creates special care requirements, or that affects the gemstone’s value. Likewise, if a material is synthetic, it must be disclosed. Jewelers, who are members of Jewelers of America, uphold a high code of professional practices and commit to disclosing all such information, in the belief that a well-informed jewelry purchaser is a satisfied purchaser.