June 24, 2021
The shape and quality of cutting is also an important factor. For jewelry emeralds became popular cut in the form of a rectangle with truncated corners – the so-called “emerald” cut, it can be called «octagon”. But there are, of course, other forms too. For example, ovals and pears are also very popular. The proportions of angles of facets in an emerald should be such that stones must look bright, doesn’t have a “window” in the center, i.e. a light area through which rays of light flows away. Cabochons are made of opaque emeralds or with a low clarity. As for faceted stones, as for cabochons, it is important the presence of symmetry, correct proportions and a good polishing.
In the photo: emerald 20.95 ct with large window in the center.
“Practical advice. Judge the attractiveness of form and quality of cutting at whole. Pay attention to symmetry. Is there a window in a stone, how does it affect beauty? Is a pavilion of a stone too deep? Look at the quality of polishing, the absence of scratches and chips on the surface of facets and edges. Many not very serious surface defects can be easily eliminated by recutting, which is quite inexpensive.“
Filling cracks with different substances is a common practice for particular all emeralds on the market. Oling and impregnation with polymers, for example, epoxy resin, are wide-spread methods. Such processing is aimed on clarity enhancement, because cracks during this become less visible. This factor of the presence or absence of enhancement also affects the price. Untreated natural emeralds very rarely appear on the market. And such stone can cost in times higher than treated one with close appearance. Level of filling with different substances also impacts on price. The larger volume of filler, for example, oil, is in a sample, the lower price is. The type of filler can also affect cost per carat. Cedar oil is considered by the majority of market players to be a traditional method of processing, and they trust it more than artificial resin. Over time, oil may leak, and then some cracks may become more noticeable. Oil can be removed from an emerald and then it can be filled with higher quality oil. Epoxy resin can’t be deleted from cracks, and there is a risk of changing color or deterioration of opacity of filling epoxy resin, so it could ruin their beauty. Visually, the presence of oil or other filler in emeralds can be seen only possessing some experience. It should be guided that the more cracks in the sample going to the surface of the stone are, the more filler can be in that stone. Very rare and expensive high clarity emeralds without cracks, which have not been enhanced, usually have an accompanying certificate, confirming that they do not contain filler.
In the photo: information about emerald enhancement in certificate
Mining is processed mainly on deposits of following counties: Colombia, Brazil, Zambia, Afghanistan and Pakistan. From time to time emeralds are mined in Russia, in the Ural Mountains, but it is difficult to find good quality uralian samples. The Malysheva Mine from the Urals supplies stones to the world market that are highly valued abroad. The Uralian samples (from Russia, the Urals) are characterized by the presence of a slightly yellowish tint in color.
The factor of an origin significantly affects the cost. Therefore, it is important where emerald were mined, in which country. Historically, the best in color are emeralds from Colombia. Thus, the word “Colombia” for this stone became a kind of high quality guarantee. Now it is like a brand. Although it is clear that Colombian emeralds come of different quality, not only the best. Also specimens mined in other countries may be no worse in color or clarity than Colombian emeralds. But in comparison with similar samples from Colombia they will cost less. Colombia has the richest emerald deposits. The most famous deposits are Muzo, Coscuez, and Chivor. Afghan emeralds can display fairly high quality. In recent years, mining has been actively pursued in Zambia. Treated Zambian emeralds often have a light grayish tint. Gemfields company leads industrial mining in Zambia. Many people bring faceted emeralds from India. This is due to the fact that India is the main center of cutting emeralds from different deposits of the world. And actually Indian emeralds, mined in India, now in the country are almost none.
“Practical advice. Ask the seller about a certificate. Where was a stone mined? Was it treated? If so, what is the degree of filling a stone? These questions can be answered in certificate or directly by sellers. “
Among all the emerald types are as follows: stones with the effect of a cat’s eye and «trapiche” variety. The effect of the cat’s eye or, in another way, the effect of a running light strip, manifests itself in stones cut in a cabochon form, due to presence of elongated parallel needle inclusions or channels inside. Crystals of trapiche type has inclusions of graphite, situated as sectors. If cross section cut is made, you see that graphite inclusions look like 6-ray star inside a crystal. Trapiche emeralds comes mainly from Colombia. These types are rarely found in jewelry. Both varieties has huge value for collectors.
In the photo: trapiche emeralds from Columbia
– In the first part of the article we spoke about main factor of emerald choice: color, clarity and weight.
– In the third part we will show you real prices per carat.
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