The green emerald, May’s birthstone is often thought of as a symbol of rebirth, bringing good fortune and youth. The word ‘emerald’ is derived from the ancient Persian word ‘smaragdus’ which meant ‘green’.
Emeralds can be found in many places around the world, but most emerald is of low quality, so treatments to improve colour and quality are normal.
Emerald is from the same family of stones as aquamarine and can be found in six-sided crystals up to 30 cm in length. The characteristic green colour can vary from light to dark shades, the most highly prized, and rarest, are the deepest green with an intense greenish blue hue.
The History Of Emeralds
Emeralds have a long history, every ancient civilisation treasured them. In India emerald was called ‘marakata’ or ‘the green glowing’, emeralds in the region came from Swat, in modern day Pakistan. The Persians called emerald ‘smaragdus’ which over time moved through Latin and into English as emerald. The original meaning of the word was ‘green’.
Emeralds have been known to the ancients for as long as 6000 years with records of their sale in markets going back that far.
In South America, the Muzo Indians of Colombia had emerald mines. They were well hidden so when the Spanish conquistadors arrived it took them 20 years to uncover them.
The oldest known commercial emerald mining took place in Egypt in about 330 BC. Cleopatra was probably the most famous fan of emeralds, even claiming ownership of all emerald mines in Egypt while she reigned.
Today the best emeralds are reputed to come from Colombia due to their transparency.
The Mythology Of Emerald
The long history of emerald means that many cultures have had different ideas about the emeralds they prized so highly. The Chaldeans believed that emeralds gave them a connection to their gods. Islamic cultures have engraved verses of the Koran onto emerald, and it is said that Emperor Nero of Rome used a transparent emerald to watch gladiator fights because he found the effect soothing. In the European middle ages, emeralds were worn by women to keep them chaste. In ancient Greece, Hippocrates prescribed ground emerald in a lotion to soothe the eyes.
Many cultures recognise the emerald as having a calming, protective effect.
The Geology Of Emeralds
Emeralds are crystals, their natural form is a six-sided shaped and can be up to as long as about 30 cm. Emerald crystals grow just one molecule at a time and take hundreds of millions of years to form.
Emerald is a form of beryl, a commonly found crystal. The various colours of the beryl family of gemstones are due to differencing impurities that found their way into the liquid magma formed of beryllium aluminium cyclosilicate that is the basis of the crystals. Emerald is formed in areas where there was molten quartz near a source of chromium or vanadium. Emeralds get their green colours from the trace amounts of chromium and occasionally vanadium. Because emeralds usually have many inclusions, they can be quite brittle.
High-quality emeralds are found in many locations around the world including Colombia, Zambia, Zimbabwe, Brazil, Madagascar, India, Pakistan, the United States, Afghanistan and Russia.
Due to the rarity of high-quality gemstones processes have been developed to create synthetic emerald. Crystals are grown in laboratories at a rate of 1 mm per month. Typically, production lasts for 7 months giving rise to gems of 7 mm in length which are then cut and faceted for jewellery.
Emeralds In Jewellery
Emerald is the most popular of all the coloured gems. In the United States, given that the definition of emerald is based on colour there is sometimes dispute as to what a stone might be. If a gem is coloured by chromium, then they say the stone is an emerald, but if the colouring is due to vanadium, they insist that the stone is called green beryl. In Europe, we do not make this distinction, and any green beryl is called emerald. This means that, as a buyer, you should insist on buying a stone with a rich green colour, not a faint pale green.
Emerald has a Mohs Scale hardness of 7.5 to 8; usually, this would be considered hard enough for most jewellery purposes. However, most emeralds contain several inclusions or imperfections in the crystal which make the stone brittle and more likely to break. Most emeralds have flaws that can be seen with the naked eye.
Most emeralds are treated to improve their appearance. The goal is to fill the cracks in the gem and reduce their visible effect. While these treatments might improve the visual appearance of the gem, they do nothing for the strength. Over time, many treatments can alter in colour and deteriorate.
Due to the inherent fragility of emeralds, it is best to use them in pieces not subject to knocks and impacts such as earrings or pendants. If used in a ring, then it should be used only on special occasions.
Cleaning of emeralds should be carried out carefully. Use of chemicals or ultrasonic devices is not recommended as these can remove the treatments used to minimise the appearance of fractures. The best cleaning is with warm, slightly soapy water and allowing the stone to air dry. Clean only occasionally, when necessary.
Enjoy the green fire of the emerald with all its flaws. The owner of a piece of emerald jewellery will be proud of it. The unmistakable colour is loved everywhere, and the owner of a beautiful piece of emerald jewellery will always have reason to be joyful!