Jewelry Stores : EMERALD

Emerald is a member of the Beryl family, which consists of Beryl (commonly green) itself, Aquamarine (blue), Morganite (pink), Heliodor (yellow) and Goshenite (colourless). Only green Beryl containing chromium is classed as emerald, because it is this impurity that gives the gem its beautiful colour.

Emerald is rarely free of inclusions and these are sometimes referred to as the ‘garden’ of the stone. Colour is all-important in emerald, inclusions are secondary. Look through the table of one with a magnifying glass and explore, it can be a wonderland. A perfect emerald can outrank a diamond in value.Fractures are also common, which raises the controversial subject of filling. Filling has been used for very many years and consists of glass or resins. Oils are often used to improve the appearance. Arguments have been going on in the trade as to whether filling or oiling should be declared. The general feeling is no, but agents to improve the colour must be stared.Emeralds must be handled with care: any oil used to improve the appearance will be removed by overheating or detergents, so be careful.Ultrasonic cleaners should also be avoided, as they can cause the stone to shatter, so specify this to your jeweller should you take your jewellery in for cleaning or repair. A reputable jeweller will already be aware of this. Even repairs to a ring where heat is required can damage any filling the stone has received and weaken ft.The current sources of emerald are Colombia, Brazil, Russia, Australia, South Africa, India plus a few minor sources. Recently, finds of gem quality have been made in Canada. A rare form of emerald, the Trapiche {tra-PEE-chee), is only found in Colombia. Its name comes from the spoked cog-wheel used to grind sugarcane, as the stone displays a spoke-like pattern, which gives a six-pointed star effect.

Large emeralds are very rare, particularly those of good colour. One of the biggest found in the early nineteenth century in Colombia was the ‘Devonshire’, which weighed in at 1383.95 carats uncut.

Fakes and frauds

Because emerald is such a valuable stone simulants abound. The value and popularity can be judged by the enormous trade in smuggled stones costing governments, such as that of Brazil, hundreds of millions of pounds a year.

Common simulants are doublets and triplets as shown earlier: often referred to as ‘Soude’ emeralds.The triplets are two pieces of quartz with a green gelatine layer sandwiched between, although other materials may be used to create the same effect. The painting of the backs of natural pale emeralds has also been tried.Several companies produce synthetic emerald legitimately, the best known being the American company Chatham. (Gilson, which was one of the forerunners of synthetic emerald, was taken over by Chatham in the late 1990s). Originally synthesised in the early 20th century, it was only with the emergence of Gilson and Chatham in the 1930s that synthetic emeralds began to take their place as an accepted alternative to the natural gem in the jewellery trade.

Chemically identical to the natural stone and virtually undetectable by the layperson, synthetic emeralds sell at about a tenth of the price of the real stones. Russia and Japan also produce synthetics.

As the availability of natural emerald from the classic source of Colombia fluctuates due to mines being closed down on a regular basis caused by criminal activity, synthetics will always be there to satisfy demand for one of the most popular of gems.The Chelsea Filter was initially developed to identify the numerous simulants from the real emerald stones, which show red under the filter due to the chromium present. However, the Gilson & Chatham synthetics also show red under the filter, but to differing degrees. Other green simulants mostly do show green under the Chelsea Filter except demantoid garnet and zircon,which show pinkish. Chrome tourmaline a beautiful green gem will also show red under the filter. Yet another snag is that some emeralds contain iron and so do not show red at all under the filter. I am afraid you must rely on a gemmologist to confirm the identity.

Emeralds have always been a popular gem to synthesise and simulate so it is still possible to find early examples of these. Lechleitner synthetics consisted of a piece of faceted common beryl with a thin coating of synthetic emerald ‘grown’ over to give the appearance of a solid stone. This would give all the characteristics of a natural stone. These appeared in the 1960s.