Why Are Emeralds Valuable?

Natural Stones

• As of 2009, South America was the major producer of fine emeralds from Colombia and Brazil, followed by Africa (with mines in Zambia, Zimbabwe, Madagascar and Nigeria). Although other mines exist on other continents, their stones are generally of poorer quality.

  Emeralds are mined by flux and hydrothermal methods; the equipment is expensive and requires large amounts of energy. In addition to taking a long time to produce, mining yields few gems, which makes emeralds hot property.

Inclusions

• Emeralds are considered "Type III" gemstones by the Gemological Institute of America, meaning that almost all mined emeralds have inclusions. Over 90 percent of mined emeralds sold have been treated with oil, resin or epoxy to reduce the appearance of inclusions. Synthetic (lab-created) emeralds are less valuable than natural. When first designed, synthetic stones rarely had inclusions, which made them easier to spot. As more were created, imperfections were included, which makes these emeralds appear more like the real thing (at least to the general consumer).

Color

• Color varies by location; Russian stones tend to be cloudy, Australian stones are pale and Brazilian stones are usually yellow-green. The color is due to chromium and iron levels.

  Emeralds are dichroic, meaning they exhibit two different colors when viewed from two different directions---blue-green and yellowish-green. The most desirable color in an emerald is a strongly or vividly saturated medium-dark blue-green.

Size

• Like many gems, the larger the stone and the fewer inclusions within, the higher the per-carat price. Large top-quality emeralds are uncommon, and although smaller pieces may be lovely, an emerald can truly show its beauty above a certain size. A top-quality emerald may actually cost more than a diamond that weighs the same amount. Poorer stones are cut to be beads or cabochons.

Warning

• Cleaning treated emeralds with steam, solvents or ultrasonic devices can remove the oils or epoxy used to improve the stones' appearance, causing their imperfections to become noticeable again. The more noticeable the imperfections, the less valuable the stone, and the more its structural integrity is compromised. Clean emeralds only with mild soap and warm water, and avoid wearing them if they may be treated roughly. However, it is possible for emeralds to be retreated to regain their previous beauty.