Emerald

Emeralds

Emeralds are fascinating gemstones. They have the most beautiful, most intense and most radiant green that can possibly be imagined: emerald green. Inclusions are tolerated. In top quality, fine emeralds are even more valuable than diamonds.
The name emerald comes from the Greek 'smaragdos' via the Old French 'esmeralde', and really just means 'green gemstone'.

Emeralds, like all colored gemstone are graded using four basic parameters–the four Cs of Connoisseurship: Color, Cut, Clarity and Crystal. The last C, crystal, is simply a synonym for transparency.

The world of fine emeralds

Colombia continues to be at the top of the list in terms of the countries in which fine emeralds are found. It has about 150 known deposits, though not all of these are currently being exploited. 

The best known names are Muzo and Chivor, where emeralds were mined by the Incas in pre-Columbian times. In economic terms, the most important mine is at Coscuez, where some 60 faces are being worked. 

According to estimates, approximately three quarters of Colombia's emerald production now comes from the Coscuez Mine. Colombian emeralds differ from emeralds from other deposits in that they have an especially fine, shining emerald green unimpaired by any kind of bluish tint. The colour may vary slightly from find to find. This fascinatingly beautiful colour is so highly esteemed in the international emerald trade that even obvious inclusions are regarded as acceptable.

But Colombia has yet more to offer: now and then the Colombian emerald mines throw up rarities such as Trapiche emeralds with their six rays emanating from the centre which resemble the spokes of a millwheel.

Even if many of the best emeralds are undisputedly of Colombian origin, the 'birthplace' of a stone is never an absolute guarantee of its immaculate quality. Fine emeralds are also found in other countries, such as Zambia, Brazil, Zimbabwe, Madagascar, Pakistan, India, Afghanistan and Russia. Zambia, Zimbabwe and Brazil in particular have a good reputation for fine emeralds in the international trade. 

Excellent emerald crystals in a beautiful, deep emerald green and with good transparency come from Zambia. Their colour is mostly darker than that of Colombian emeralds and often has a fine, slightly bluish undertone. 

Emeralds which are mostly smaller, but very fine, in a vivacious, intense green come from Zimbabwe's famous Sandawana Mine, and they often have a delicate yellowish-green nuance. And the famous emerald mines of Colombia currently face competition from right next door: Brazil's gemstone mine Nova Era also produces emeralds in beautiful green tones, and if they are less attractive than those of their famous neighbour it is only by a small margin. 

Brazil also supplies rare emerald cat's eyes and extremely rare emeralds with a six-spoked star. Thanks to the finds in Africa and Brazil, there are more emeralds on the market now than there used to be - to the delight of emerald enthusiasts - .

Color

In gemology, color is divided into three components:hue,saturation& tone. Emeralds occur in hues ranging from yellow-green to blue-green, with the primary hue necessarily being green. Yellow and blue are the normal secondary hues found in emeralds. Only gems that are medium to dark in tone are considered emerald; light-toned gems are known instead by the species name green beryl.

 The finest emerald are approximately 75% tone on a scale where 0% tone would be colorless and 100% would be opaque black. In addition, a fine stone should be well saturated; the hue of an emerald should be bright (vivid). Gray is the normal saturation modifier or mask found in emerald; a grayish-green hue is a dull green hue

Clarity

Emerald tends to have numerous inclusions and surface breaking fissures. Unlike diamond, where the loupe standard, i.e. 10× magnification, is used to grade clarity, emerald is graded by eye. Thus, if an emerald has no visibleinclusion to the eye (assuming normal visual acuity) it is considered flawless.

Stones that lack surface breaking fissures are extremely rare and therefore almost all emeralds are treated ("oiled", see below) to enhance the apparent clarity. Eye-clean stones of a vivid primary green hue (as described above) with no more than 15% of any secondary hue or combination (either blue or yellow) of a medium-dark tone command the highest prices. 

This relative crystal non-uniformity makes emeralds more likely than other gemstones to be cut intocabpchons, rather than faceted shapes.

Treatments

Most emeralds are oiled as part of the post-lapidary process, in order to improve their clarity. Cedar oil, having a similar refractive index, is often used in this generally accepted practice. Other liquids, including synthetic oils and polymers with refractive indexes close to that of emerald such as Opticon are also used. 

The world of fine emeralds

Even if many of the best emeralds are undisputedly of Colombian origin, the 'birthplace' of a stone is never an absolute guarantee of its immaculate quality. Fine emeralds are also found in other countries, such as Zambia, Brazil, Zimbabwe, Madagascar, Pakistan, India, Afghanistan and Russia. 

Zambia, Zimbabwe and Brazil in particular have a good reputation for fine emeralds in the international trade. Excellent emerald crystals in a beautiful, deep emerald green and with good transparency come from Zambia. Their colour is mostly darker than that of Colombian emeralds and often has a fine, slightly bluish undertone.

Emeralds which are mostly smaller, but very fine, in a vivacious, intense green come from Zimbabwe's famous Sandawana Mine, and they often have a delicate yellowish-green nuance. 

And the famous emerald mines of Colombia currently face competition from right next door: Brazil's gemstone mine Nova Era also produces emeralds in beautiful green tones, and if they are less attractive than those of their famous neighbour it is only by a small margin.

Brazil also supplies rare emerald cat's eyes and extremely rare emeralds with a six-spoked star. Thanks to the finds in Africa and Brazil, there are more emeralds on the market now than there used to be - to the delight of emerald enthusiasts - . 

Emerald in different cultures, and emerald lore

Emerald is regarded as the traditional birthstone for May, as well as the traditional gemstone for the astrological sign of Taurus , Gemini and sometimes Cancer.