7 Things You Never Knew About Emerald Gemstones
Emerald is the traditional birthstone of May, along with agate and is also associated with the 55th wedding anniversary. It is also, to a lesser degree, with the zodiac sign Cancer. But there is a lot more to know about emerald and here are some of the most interesting bits.
It is the same family of stones as peridot
Emerald is a member of the beryl family of stones and is given its beautiful green colour by a mineral called chromium, sometimes vanadium. As a rule, beryl stones are pretty tough, with a Mohs scale hardness of 7.5-8 but because emeralds have lots of inclusions, they tend not to be as hard.
Emeralds are graded the same as diamond
Emeralds are graded in the same way as the other main gemstones using four parameters – colour, cut, clarity and carat weight. Colour is top of the list in importance but clarity is nearly as important with emeralds. To be a top stone it must have a verdant green hue but also a high degree of transparency.
Colour itself is divided into three components – hue, saturation and tone. Hues can range from yellow green to blue green but all have to have green as the main colour. They also need to be dark green, as light toned emeralds are classified instead as green beryl.
Emeralds come from around the world but the most are from Columbia
Emerald has been mined in places such as Egypt and India since ancient times and in Austria since the 14th century. Today, Columbia is the world’s top producer with an annual production varying between 50% to 95% of the world population. Zambia is the next largest producer with the Kafubu River area being responsible for around 20% of the world’s production in 2004.
Other countries that have emerald deposits include Afghanistan, Australia, Brazil, Bulgaria, Canada, China, France, Germany, Madagascar, Namibia, Nigeria, Pakistan, Russia, South Africa, Switzerland, the US and Zimbabwe. In the US emeralds come from Connecticut, Montana, Nevada, North and South Carolina.
It is one of the four precious gemstones
Emeralds are one of the four precious gemstones that the world recognises – with ruby, sapphire and diamond – and is often worth more than diamonds because each has imperfections that make it very rare. Because emeralds have a lower density, a one carat emerald can seem to be bigger than a one carat diamond.
Inclusions are natural but mean cleaning is tricky
The inclusions in emeralds can cause a lot of problems so they can’t be cleaned with mechanical cleaners – old fashioned warm water and a hand cleaner is the best bet. Lots of emeralds are treated by filling with oil to prevent unintentional chipping or cracking.
Queen Cleopatra was a big fan
Some of the oldest emeralds known to man are around 2.97 billion years old and the first were known to have been mined in Egypt in 1500BC – it was the favourite stone of Queen Cleopatra.
The Spanish brought emeralds from South American, where the Incas had been using them for hundreds of years. The Spanish then used them to trade for precious metals.
Famous emeralds
The Duke of Devonshire emerald is one of the largest uncut emeralds in the world, weighing 1,383.93 carats. It was mined in Muzo, Colombia and was given by Emperor Pedro I of Brazil to William Cavendish, 6th Duke of Devonshire in 1831. It was exhibited in London at the Great Exhibition of 1851 and more recently in the National History Museum in 2007.
The Gachala emerald is one of the largest emeralds in the world at 858 carats. It was found in 1967 in a Colombian mine in the town of Gachala and was donated to the Smithsonian by Harry Winston.
The Chalk Emerald is 37.82 carats and comes from Colombia. It was originally owned by the rulers of Baroda State, a princely state of India, who wore it at the centrepiece of an emerald and diamond necklace that was worn by the Maharani Saheba then her son Maharajah Cooch Behar. It was recut slightly in the 20th century and set into a ring by Harry Winston Inc. surrounded by 60 pear shaped diamonds. It was donated to the Smithsonian in 1972.
The Mogul Mughal emerald weighs some 217 carats and is rare as it is dated 1107 AH which corresponds roughly to the year 1695, the reign of Aurangzeb, 6th emperor of the Mughal Empire. It was sold in 2001 by Christie’s auction house for £1,543,750 and as of 2008 was on show in the Museum of Islamic Art in Doha, Qatar.
The Bahia Emerald is a very large emerald and contains the single biggest shard ever found. It also has a busy history! The stone weighs around 840lb and contains more than 180,000 carats and came originally from Bahia, Brazil. It was nearly lost during the flooding of New Orleans by Hurricane Katrina when it was in storage and was then reported stolen in 2008 from a secure vault in South El Monte, Los Angeles. Some say the stone is worth $400 million and at one point it was listed on eBay for $75 million – buy it now!
