Like the diamond and other gemstones, emeralds can be judged according to the 4Cs: color, cut, clarity, and carat weight. These gems are highly prized, and intensely colored ones can be quite rare, so make sure that you visit a trusted AGS jeweler who can help you make an informed investment.
Most gemologists agree that it all comes down to color when purchasing an emerald. Color should be evenly distributed and not too dark. Rare emeralds will appear as a deep green-blue, while lighter colored gemstones are more common (and therefore, often more reasonably priced).
Like other beryls, emeralds often have inclusions that are visible without a microscope. Most gemologists readily accept this about these gemstones and don’t detract too much from the overall value of the stone when inclusions are present. It's all about the vibrant color and saturation of the gemstone!
Cut is very important on an emerald because it helps to maximize that desirable green color. Many emerald gemstones are cut into an emerald shape—an elongated, rectangular shape with step-cut facets—which helps to make a bright stone with sparkle while minimizing inclusions or fissures.
Unlike some gemstones, which can maintain a relatively standard price range no matter the size, you will see a wide price range between smaller emeralds and larger ones. Some of the most famous emeralds in private collections or museums today are literally hundreds of carats and are considered to be priceless. Angelina Jolie, Elizabeth Taylor, and the British monarchy all have worn famously large and beautiful emerald gemstone jewelry.
If you’re not quite in the market for a statement tiara, have an American Gem Society gemologist help you pick the right gemstone and setting for your budget. You may choose to opt for a smaller, more intensely colored gem over a larger, lighter one, though it all comes down to personal jewelry and color preference in the end.