When we mention the emerald we always picture a beautiful, elegant emerald green hue. This shade of green so clearly defined by association that it is widely regarded as the colour “emerald green”. We hope that you will not feel cheated of these beautiful images of colour which the word “emerald” evokes, when we tell you that the emerald’s colouration comes from the presence of chromium oxide. A higher concentration of oxides creates a bright green emerald, while a lower quantity contained in the emerald results in dark green. The presence of iron and vanadium gives a greenish yellow hue, which is less appreciated in lapidary production.
The word emerald according to some authors originated from a word of old Persian and Sanskrit - smarana, which means 'remembrance'. So it was consider a recollection to something, maybe even a warning. Another group believes that the Greek origin of the word - smaragdos, a Greek word for emerald. In ancient times all green gems were called emerald.
Emeralds of superior quality must be absolutely clean and transparent. Such examples are, of course, rare and very expensive. (The four “Cs” of Gemmology — Clarity, Colour, Cut and Carat — will most often determine value, even today when people’s taste is changing, and the market is determining values without great reference toexpert opinions.) Emeralds often have various natural inclusions caused by gas bubbles or flux, or by small crystal forms within. These are all known by the French term givrés — frost. The presence of these inclusions, especially in larger number, diminishes the value of emeralds. A very important feature by which we can recognise if something is a true emerald is the presence of “frost” inclusions, i.e. moss-like accumulated inclusions in the stone. Emeralds often have nuanced colours and a variety of stretch marks and lines which, of course, have a significant impact on their quality and price.
Emerald stone has vitreous lustre, and the jewellery is substantially more appreciated if gemstones are darker green in colour, especially if they possess a satin glow. It is a type of Beryl stone, one of most popular and well known mineral groups. It occurs in a variety of colours and gemstones arrays like emeralds, aquamarine, goshenite, morganite…
The stone’s hardness on Moh’s scale is 7.5–8, which is why it is, so to speak, insensitive to the effects of dust and is long-lasting. Also, the emerald is resistant to acid and other chemical agents.
The exploitation of emeralds was first recorded with reference to the mines, in Egypt, near the Red Sea. Data shows that exploitation in this area started during the reign of the emerald Pharaoh Sesostris, called the Black Pharaoh, some 3500 years ago! Emerald was a favourite gemstone of the Ancient Egyptians. This stone is often found with Egyptian mummies, as it symbolises eternal life. Cleopatra, the Egyptian Queen, loved to dress in robes decorated with emeralds, and gladly donned the gemstone on all official occasions. Papyrus Prisse dated 2500 BC, refers to a good thing, though difficult to find: a gemstone called emerald, which slaves can detect in the edges of the rocks.
In Ancient Rome, emeralds were considered the most precious stones along with sapphires. (This may have had something to do with Cleopatra’s generous hands and other parts of her body, but surely reflected the fact that diamonds and rubies were extremely rare). Emerald was also present on breastplate of the High Jewish priest Aaron. It was a symbol of the Jewish tribe, Ruben (and not rubies as one may think because of the name).
The subsequent history of the emerald is linked to South and Central America, where there were numerous sites of discovery dating from the time of the Incas. Huge interest in emerald began after the discovery and conquest of the American continent. In his book Conquistadors America, William Hickling Prescott (May 4, 1796–January 28, 1859) describes that, among other treasures, the Spanish conquerors found a skull crowned with a huge emerald in shape of a pyramid, in the royal palace Tetoko. From the time of the Spanish conquest until today, the Muzo and Chuvor mines in Colombia have been among the most significant sources of emeralds. In Colombia, there is even a state corporation for emerald production called “Columbia Emerald Enterprise”.
Besides Colombia, Brazil is an important site for emerald mining, but the quality is considered lower than that of Colombia. Russia has also played a role in the industry, where emeralds were discovered in the Urals in 1830. These stones are also of poorer quality, mainly vague in colouring, greenish-yellow, and are found together with alexandrite. South Africa also has significant deposits (mines Cobre and Somerset in Northern Transvaal), followed by Zimbabwe and Western Australia. Emerald sites in Europe are now mostly depleted, but collectors can find rare examples in Central Europe and Salzburg (Austria).
Processing emeralds is primarily determined by individual quality. The highest quality specimens can be processed into many different forms. The most widespread way of cutting the stone is into the form of rectangular or square plate, with stepped-treated sides. This is known as “emerald cut”. Specimens of poorer quality are processed en caboshon.
An emerald ring, the stone of which is surrounded by many small diamonds of brilliant cut, is often considered to be jewellery of exceptional quality. Jewellers point out that intense emerald green colour must be installed in the colourless socket — a jour. If the emerald has a lighter green colour, the bottom of the socket should be green, and if it has a “frost”, cracks or other inclusions, then the bottom should be covered with a dark colour.
There are many famous emerald pieces of jewellery worn by notable historical figures. One of them is a magnificent ring called Maximillian’s Emerald, worn by Ferdinand Maximilian Joseph, Emperor of Mexico who was executed in 1864 (hopefully not because of the stone, but I have a feeling it was one of the reasons). The stone was 21.04 carats, clear as sea water and with similar dark green colour. It is presently on exhibition at a Gem Gallery of Smithsonian Museum of Natural History.
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