The oldest Emeralds ever found are from South Africa, and they date back 2.97 Billion years. So it is safe to say this is one special gemstone specimen. The first known Emerald mines were in Egypt, from about 330 BC, and it is known that it was a favourite with Cleopatra, as she used it in many of her royal adornments. Emerald is the most well-known member of the Beryl family, which also includes Aquamarine and Morganite. Pure Beryl is colourless, but as with most coloured gemstones it is the presence of minor impurities that have an impact on the appearance and therefore classification of these gemstones.
Moh's Hardness Scale
In general, Emeralds are highly included gemstones, and thus their resitance to breakage (brittleness) is quite poor. It is therefore advised to use Emeralds in dress rings /cocktail rings/ occasion rings, and to not wear them every day. Oil filling is a common treatment to make the inclusions appear less obvious. The lush green colour in Emeralds are caused by the presence of Chromium, and sometimes Vanadium whilst the gem is forming. Colombian Emeralds are highly coveted, because of their incredible brilliance and fire. The two main Emerald belts are in the Eastern Ranges of the Colombian Andes: Muzo and Coscuez.
A square Radient cut Emerald.
Emerald in bedrock with Calcite from Muzo, Colombia.
Colour grading in Emeralds determine the value, as well as clarity – much like Diamond valuation. Some Beryl are deemed too light to be called an Emerald, so they are classified as ‘Green Beryl’.