Indian Gemological Identification

EMERALD

Emerald is a gemstone and a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of  chromiumand sometimes vanadium. Beryl has a hardness of 7.5–8 on the Mohs scale. Most emeralds are highly  included, so their toughness (resistance to breakage) is classified as generally poor. It is a cycosilicate.

Properties

Emeralds, like all colored gemstone, are graded using four basic parameters–the four Cs of Connoisseurship: Color, Cut, Clarity and Carat weight. Before the 20th century, jewelers used the term water, as in "a gem of the finest water", to express the combination of two qualities: color and clarity. Normally, in the grading of colored gemstones, color is by far the most important criterion. However, in the grading of emeralds, clarity is considered a close second. Both are necessary conditions.

Treatments

Most emeralds are oiled as part of the post-lapidary process, in order to fill in surface-reaching cracks, improving their clarity and stability.

Mining

Emeralds are found all over the world in countries such as Afghanistan, Australia, Brazil, Bulgaria, Cambodia, Canada, China, Egypt, Ethiopia, France, Germany, India, Italy, Kazakhstan, Madagascar, Mozambique, Namibia, Nigeria, Norway, Pakistan, Russia, Somalia, South Africa, Spain, Switzerland, Tanzania, USA, Zambia and Zimbabwe. In the US, emeralds have been found in Connecticut, Montana, Nevada, North Carolina and South Carolina, in 1997 emeralds were discovered in the Yukon.

Synthetic Emerald                                 

Both hydrothermal and flux-growth synthetics have been produced, and a method has been developed for producing an emerald overgrowth on colorless beryl.

Crystal Structure : Hexagonal

Composition        : Beryllium Aluminium Silicate

Hardness            : 7.5 – 8.0

Refractive Index  : 1.57 – 1.59

Specific gravity   : 2.63 – 2.91