An emerald is an exquisite jewel. Emeralds are among the traditional “Big Three” of gemstones along with Rubys and Sapphires.

An Emerald is appreciated and graded by its verdant, green color. It is the emerald’s color that most significantly weighs on its value.
A highly saturated emerald will outprice larger emeralds with less appealing color consistently, despite the rarity of larger gem sizes. Color is also not as complicated in emeralds as it is in other gems because emerald green is a very limited range from slightly yellowish green to bluish green. The intensity of the green in the finest emeralds might not be equaled by anything else in nature. Chromium, vanadium, and iron are the trace elements that cause emerald’s color. The most desirable emerald colors are bluish green to pure green, with vivid color saturation and tone that’s not too dark. The most-prized emeralds are highly transparent. Their color is evenly distributed, with no eye-visible color zoning. If the hue is too yellowish or too bluish, the stone is not emerald, but a different variety of beryl, and its value drops accordingly.

Unlike diamonds, where the loupe is used to grade clarity, emeralds are graded by eye. Emeralds are known for being included. They are a Type III gemstone, which means they almost always show inclusions. The few emeralds that do not dispaly impurities with the naked eye will be as much as two to three times more expensive.  with emeralds with similar color and carat weight. When an emerald has no visible inclusions to the naked eye it is considered flawless.
The evocative term jardin, French for “garden,” is used to refer to this variety. The types of inclusions in emeralds can help identify their sources. See the tables below.

Most emeralds are treated (“oiled”, see below) to enhance the apparent clarity. Unlike Rubies and Sapphires, Emeralds are never heat treated to improve color or clarity. Instead, Emeralds are typically treated with oil or other “fillers”. The purpose of this is to draw the filling substance into any surface-reaching fissures (on a microscopic level) to improve the clarity of the Emerald. Emeralds which undergone no treatment are significiantly more expensive. This will be spedcified in the certificate. 

Emeralds have various sources, but one of the oldest continuing suppliers is the Muzo mine in Colombia. Natives of this area had been collecting emeralds from this source for a long time before the area was abandoned and eventually rediscovered in the 1700s by the Spanish conquistadors. Muzo is known for having perfectly green colors, however this is not ideal emerald color.

Chivor, Colombia is known for emeralds with a bluish component, which is the ideal emerald color. The third large emerald mining district is Cozcuez, also in Colombia, which is known for a more yellowish color. However, these are only guidelines for the colors of emeralds from these locations, though they are used to compare the color of emeralds from all other mines in Colombia.

Much like the various mines of Colombia, Brazil, Ethiopia and Zambia have certain colors attributed to their emeralds (yellowish and bluish emeralds respectively). There are no strict rules, since various emerald sources have colors that frequently overlap.

DiamondsAntwerp.com only offers natural Emeralds.