By Alex Duffy, Jewellery Specialist at Fellows Auctioneers.
Known historically as ‘smaragdus’, the ancient Greek word for green, emerald has long been admired and adorned. The first know mines can be dated back to around 330BC, where Cleopatra was known to have yielded the precious stone. Earlier recounts of ‘smaragdus’ do exist, but it is unclear whether these references actually relate to emerald or just other green materials.
Legends associate emerald with a number of magical and healing properties, with the stone believed to bestow the wearer with foresight, protect against evil spells and even cure diseases such as malaria. One other property is that it was believed to restore ones eyesight and remove weariness due to the soft green colour. This actually has some truth to it, as green is scientifically proven to relieve stress and eye strain and in the words of Pliny the Elder, “nothing greens greener”.
From a gemmological point of view, emerald is the verdant variety of the mineral beryl. The same mineral group that includes the precious stones aquamarine, heliodor and morganite. The luxurious green colour generally derives from chromium being present as an impurity within the chemical structure (Interestingly the same element which gives ruby its vibrant red colour). Vanadium is also known to cause green colouration in emerald, but typically it is the Cr rich beryl that produces the best and most sought after greens.
Unlike other gemstones, emerald is known for and generally accepted for its included appearance. The GIA classes them as ‘Type III’ stone, which is to say that they are almost always going to be included. Whereas like likes of ruby and sapphire can be considered low quality if they are seen to have internal fractures and inclusions, emeralds are expected to have these impurities. This is partly down to the formation of the stone, where crystallization can occur under extreme hydrothermal environments. The term ‘Jardin’ (French for garden), is sometimes used in relation to the clarity of emeralds, due to the mossy or garden-like appearance. Because of the high probability of inclusions being present, emeralds that are inclusion free are extremely scarce and high quality examples can demand huge prices.
Emerald sources can be found all across the world, with Brazil, Zambia and India being some of the most historically productive localities. However, it is the gems yielded from the mountainous regions of Colombia that are the most famous and sought after. Known for their unrivalled luxurious, soft green hues, fine examples of these South American beauties can demand huge prices. A recent auction saw a ring set with a high quality 10.04cts Colombian emerald sell for just shy of £600,000!