by Amanda Applebyinfo@amandaappleby.comMay, the month of the emerald
Traditionally the 12 months of the year are associated with different gemstones and the conventional birthstone for the month of May is the emerald.
Emeralds are part of the beryl family of gems, and their renowned colour comes from chromium and occasionally vanadium. The Mohs scale measures emeralds as having a hardness of 7.5 - 8, which makes them relatively scratch resistant, although they can chip quite easily. The ''emerald cut'' was developed to protect the stone and enhance its beauty.
Emeralds are judged predominantly by their colour, which can range from light to deep green. Most have a blue or yellow undertone, but the highest quality gems are pure, vivid green and are quite rare. To enhance the colour of an emerald the stone is treated with green tinted oils. These oils fill up any surface cracks and improve the transparency of the stone. It is vital to clean emeralds correctly using warm water and a mild detergent since steam tools, solvents and ultrasonic cleaning tend to strip these applied oils.
Columbia is the biggest supplier of emeralds and it also can boast having the world's finest quality. Other countries that mine this valuable jewel include Zambia, Brazil, Afghanistan, Russia and Pakistan.
Emeralds have been mined for thousands of years even though they can be successfully grown in a laboratory. The world's first emeralds were excavated in Ancient Egypt and are therefore are often associated with Cleopatra - it is said that emeralds were her favourite gemstones! However these ancient stones were a far duller green than the ones we recognise today.
The use of this precious stone dates back to antiquity. In Ancient Roman and Greek times it was associated with Venus and Aphrodite, the goddess of love, beauty and fertility, while during the Middle ages it was thought to assist in predicting the future. The gem is believed to have healing powers and is said to restore peace, clear the mind, improve creativity and intelligence and enhance love, commitment and loyalty.