The jewelry industry recognizes the highest quality gemstones by purity of their hue, the depth of tone, and the color saturation. The best value is in colors that include "slight" traces of other colors, are not too light or dark, and have a lot of saturated color.Nearly all gemstones today, have been treated to enhance their color. The most common methods of treatment are heating, nearly always seen with aquamarine, citrine, amethyst, sapphire, ruby and tanzanite, bleaching commonly seen with pearls, and irradiation performed on nearly all blue topaz.
Almost all gemstones contain inclusions. Even those most highly prized have at least some inclusions. Flawless gemstones are very rare and very expensive. The best value is found in gems that are lightly to moderately included. Emeralds are typically treated with colorless oil, wax or resin to minimize surface-reaching inclusions.
Unlike diamonds, with gemstones there isn't an "ideal" cut geometrically configured for maximum brilliance. A good cut showcases the gemstone's color, diminishes its inclusions, and exhibits good overall symmetry and proportion. Because gemstone color can vary, there are no hard geometrical standards when it comes to maximizing brilliance or color. Gemstones, especially rarer ones, are sometimes cut for size without regard for their color.
The carat weight of a gemstone is not necessarily an accurate gauge for gemstone size. Different gemstones have different densities (mass per unit volume), so two gems that look to be the same size may actually have very different weights. For example, a sapphire is more dense than a diamond, so a 1-carat sapphire will look smaller than a 1-carat diamond.
Nearly all gemstones on the market have been treated to enhance their appearance. Gemstones that have not been treated but exhibit desirable color and clarity command extravagant prices. Some enhancement treatments are almost universal, are permanent, and require no special care of the gemstone, such as heat treatment to enhance color. Other treatments are common, and may require more or less special care to avoid damage, such as infusion of colorless oil, wax or resin to improve clarity.
While gemstones are durable, they require varying levels of care. For example, some gemstones are especially vulnerable to household chemicals and temperature changes. Cleaning gemstones presents special challenges.
Cleaning - After removing your gemstone jewelry, clean it by following the directions on a non-abrasive jewelry cleaner. Make sure that the jewelry cleaner specifies that it is safe to use with your gemstone. Use a soft cloth to remove any remaining dirt or other residue.
- Storing - Store your gemstone jewelry in a lined case or a soft cloth, so the gems do not touch each other or parts of other jewelry. Gemstones are harder than gold, silver, or platinum and can scratch the surfaces of your other fine jewelry if they are not kept separate.
- Wear - While it's true that gemstones such as ruby and sapphire are second only to diamond on the hardness scale, it is not a measurement of their indestructibility. It means that these gemstones are able to resist scratching almost as well as a diamond. Abrasive surfaces, harsh chemicals, and sharp blows can damage even the hardest gem. Your gemstone jewelry should be the last thing you put on when getting dressed and the first thing you take off at the end of the night. Store your gemstones carefully and they will be enjoyed for generations.