Most colored gemstones derive their beauty from their color – purples, blues, greens, yellows, oranges, reds. 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.
Gem cutters work to achieve a pleasing and affordable mix of color, weight (measured in carats), 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.
Across time and cultures, people have adorned themselves with rare gem materials. From pearls and corals plucked from the seas, to bright colored pebbles found in the soils settling at the mouths of rivers; from the collection of gemstones mounted in the breastplate of Aaron as accounted in ancient scripture, to the historic gemstones mounted in the crown jewels of European monarchs, we let ourselves be known through the gemstones we choose to wear. These gemstones are precious because they are rare.
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. For some budgets, these synthetic materials are an acceptable choice.
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.
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. Some jewelers offer loose colored gemstones and are able to 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 yours 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 of America (JA) advises its members to disclose all such information, in the belief that a well-informed jewelry purchaser is a satisfied purchaser.
To give you the information you need, many jewelers provide written notice at the time you buy a gemstone by way of a note or code explaining your purchase. This information is written or stamped on the invoice or on an information card enclosed with your purchase. Be sure that the meaning of any code is clear to you. It is important to obtain this information prior to leaving the store, because it affects your purchase price and will also affect future cleaning and repair as well as replacement of an insured loss.
For more information visit the official Jewelry Information Center.