The word emerald derives from the Greek word smaragdos, which means “green stone”. Emeralds form part of the beryl group of gemstones which include, amongst others, aquamarine (pale blue) and morganite (pink). Emeralds are coloured by chromium and vanadium which give them their beautiful green hue, the depth and saturation of the colour adds to the beauty and so their value. Only the very best specimens are completely transparent, without fissures or inclusions. Inclusions in emeralds are often referred to as the Jardins of the emerald (French for garden). These naturally occurring mineral, liquid or gas inclusions enable gemmologists to distinguish between natural and synthetic emeralds and often help pinpoint where in the world the emerald formed. Emeralds found with no inclusions or fissures and of great colour are very rare and it is this rarity makes them so valuable.
The World of Emeralds
1 July 2025
Veronica Olszowska
Where are emeralds found?
Colombia is recognised the world over as the location where the best quality emeralds are found, particularly the Muzo area in the high Andes mountains of Colombia. Important deposits are also found in Brazil, India, Pakistan Zimbabwe, Zambia, South Africa and Siberia. The jardins of stones can be a very good indicator of origin as different areas have different types of inclusions, for example an emerald from Colombia might have three phase inclusions of gas, liquid and minerals such pyrite or mica, while a Siberian emerald may contain tourmaline needles.
Emerald crystal structure
Emeralds’ hexagonal crystal structure contributes to their brittleness and although emeralds score 7.5-8 on the Moh scale of hardness, they are not classified as tough gemstones. Emeralds can chip easily and so lapidarists avoid cutting them in ways that leave the stone open to damage or fracture. The best cut to protect the crystal structure of an emerald is the eight-sided step cut . This cut is used so often for emeralds that it is consequently more well known as the emerald cut.
What are treated emeralds?
History shows that gemstones have been treated by man to improve their appearance for centuries. Emeralds are treated to enhance their appearance in a variety of ways, most commonly with oils, waxes and resins.
How are emeralds treated?
Emeralds are not heat treated as they would be damaged during the process. Emeralds with surface reaching fissures are treated with oil, wax or resin. These fractures are then filled with the oils etc and in so doing the fractures are made less visible as the reflections from the surfaces of the cracks diminish. This reduction in reflection improves the clarity of the stone.
Can emeralds be dyed or coated?
Fillers that contain dye will also improve the colour of the stone. However, these manmade enhancements only temporarily improve the clarity and colour of emeralds. Over time oils can dry out or even be removed by cleaning and resins can decompose. Another treatment dreamt up by man to enhance a pale beryl is coating. The Lechleitner method, achieved by hydrothermally coating the gem material is often easy to detect as the coating is likely to craze.
How do you know if an emerald has been treated?
Oil fillers can be visible with a jewellers’ loupe as the concentration of colour in the fissures stands out. Decomposed resins become visible to the unaided eye as they produce a white substance seen within the stone. Some treatments can be hard to see with the naked eye, but they can fluoresce white or yellow under UV light. Poorer quality or damaged emeralds can be filled with polymer as it also toughens the stone. Again, detection can be difficult, but when turned the stone will show colour flashes of yellow, orange or blue from the filler. These colours which are seen as light passes through the stone are not naturally occurring and so are a good indication the stone has been treated.
Laboratory testing emeralds
State-of-the-art laboratories, equipped with Fourier Transform Infrared Spectrometry technology or Raman Spectrometry technology are able to detect fillers, but at a considerable cost. The GIA and SSEF have delineated a treatment classification system where tested emeralds are described as:
GIA Treatment Categories (Extent of Enhancement)
Nil - The emerald has no surface-reaching fissures that have been treated.
F1: Minor - Indicates a slight effect on the emerald's face-up appearance.
F2: Moderate - Represents a moderate usage of filling materials like oils or resins.
F3: Significant - Signifies an obvious effect on the emerald's appearance due to the substantial amount of filler.
The amount of filler, the size and quantity of the fractures and their location in the emerald itself all contribute to this grading, for example large fractures but with only a
small amount of filler would be classified as “minor”. Moreover, if filler is detected but is deemed not to greatly affect the overall appearance of the stone the classification could say “no evidence of enhancement.
Taking care of your emerald
Taking care of your emerald is paramount, and the right cut can contribute to the toughness of the stone while a robust setting, such as a bezel setting, can go further towards protecting the emerald from damage. Heat can fracture the stone in the workshop or evaporate the fillers and ultrasonic or steam cleaners can damage the stone or remove treatments. The safest way to clean an emerald is with warm soapy water and a soft brush.
Healing & mystical properties of Emerald: The May birthstone explained
Over the centuries emeralds have taken on greater importance than just their beauty, rarity and value. In the Book of Talismans published in 1914, the author wrote “If worn in a ring, emerald strengthens the memory and protects from giddiness”. They went on to say that it was worn “round the neck so as to lie upon the chest” by fishermen and sailors to protect them from danger at sea. It is said that healers today use emeralds to enhance emotional balance, intelligence and mental clarity and it is their belief emerald helps to rectify respiratory problems.
Emerald is the birthstone for the month of May and as such represents Taurus, the bull sign of the Zodiac, for those born between April 21 and May 20.
What are ethically sourced emeralds?
With the advent of laboratory grown gemstones, more than ever before, consumers question if a stone is natural or synthetic and care greatly if it has been ethically sourced. To be ethically mined the stone’s production must limit, as far as possible, any impact on the environment and the mining company must look after their employees with fair wages and safe working conditions.
A natural stone, from the best locations, mined in a way that protects the environment and the local people, is deemed important by today’s buyers. Buying stones and jewellery at auction is intrinsically ethical as the secondary market is the embodiment of reducing, reusing and recycling. If an emerald comes to market from the best locations in the world, without inclusions and is of a saturated deep colour, and is untreated, and certified Nil after testing, then this is extremely rare and thus dictates its value above all else.