Emerald is a precious gemstone and a variety of the mineral beryl .It has green color by trace amounts of chromium and sometimes vanadium. The name comes from the old French word 'esmeralde', which was derived from the Greek word 'smaragdos' meaning 'green stone’. . Most emeralds are highly included, so their toughness is classified as generally poor. Emerald, together with ruby and sapphire, form the "big three" of colored stones. For over 5000 years, emeralds have been one of the most desirable and valuable colored gemstones

Emerald Identification

Most of the natural emeralds contain distinct characteristic inclusions that are visible to unaided eye and almost all are treated with oil or resin to fill tiny fissures and cracks. The presence of these flaws and oil makes it quite easy to identify and distinguish natural emeralds amongst other similar gemstones. If a real emerald is placed on the eyes it gives a cool feeling, whereas an imitation becomes warm very quickly.. Due to the carbon in Emeralds, some black spots can be seen on Emerald.

Emerald Deposits

Emeralds in antiquity have been mined in Egypt since 1500 BCE, and India, and Austria since at least the 14th century CE. Today, most emerald production originates in four countries: Colombia, Zambia, Brazil, and Zimbabwe. Colombia is the international center of emerald mining. Zambia is the world's second biggest producer, with its Kafubu River area deposits (Kagem Mines).

Emerald from Zambia: Emerald crystal from the Kagem Emerald Mine, Zambia, on a matrix of quartz and mica schist. This specimen is about 6.5 centimeters in height and has the blue-green color and medium dark tone that is common in many emeralds mined in Zambia. Specimen and photo by Arkenstone / www.iRocks.com.

Emerald Hue

Emeralds occur in hues ranging from yellow-green to blue-green, with the primary hue necessarily being green.In most fine quality emeralds, color is evenly distributed, with no eye-visible color zoning. Colombian emeralds are known to have a warmer and more intense pure green color. Zambian emeralds are said to have a cooler, more bluish green color.

Emerald Clarity and Surface

Clarity is important, but inclusions are tolerated more in emeralds than virtually any other gem. Surface-reaching fractures can also be seen with the unaided eye. These flaws are not looked upon as negative attributes for emeralds. Eye-clean stones of a vivid primary green hue , with no more than 15% of any secondary hue or combination (either blue or yellow) of a medium-dark tone, command the highest prices and they are extremely rare.

Emerald Cut

As almost all emeralds have significant fractures, therefore a cut must designed to minimize the effect of those fractures on the finished stone. Due to their relative non-uniformity, the cutting of emeralds is usaually done in cabochon form, rather than faceted shapes. Faceted emeralds are most commonly given an oval cut, or the signature emerald cut, a rectangular cut with facets around the top edge. The cutter can affect color by adjusting an emerald’s proportions and number of facets.

As the name suggests, the emerald cut is the most common cut for emeralds. Courtesy Ronald Ringsrud Co.

Emerald Care and Cleaning

• Wash emeralds with warm water with a very mild detergent and after that clean it with soft or dry cloth.
• Avoid ultrasonic cleaners and steamers when cleaning emeralds as these can remove the oils that are used to enhance the emeralds.
• Store emeralds away from other gemstones and gemstone jewelry as they can easily scratch other gems, and they can easily be scratched by harder gems such as topaz and sapphires.
• Keep Emerald away from heat or wetness.

Emerald Gemological Properties

Species: Emerald - beryl

Chemical Formula: Al2Be3Si6O18 - Aluminum beryllium silicate

Crystal Structure: Hexagonal; hexagonal prisms

Color: Emerald green to green

Hardness: 7.5 to 8 on the Mohs scale

Refractive Index: 1.565 to 1.602

Density: 2.67 to 2.78

Cleavage: Indistinct

Transparency: Transparent to opaque

Double Refraction: 0.006

Luster: Vitreous

Fluorescence: Usually none