Emeralds are the best known of the green gems and reside in the top tier of precious stones. These rare gems have been known about and used in jewellery, as gifts, and traded for centuries, in societies all over the world. What we know as emeralds are the dark green variety of the mineral Beryl.

Beryl comes in a variety of colours, the best known of which, other than emerald, is aquamarine and morganite. Lighter green beryl stones are known by gemologists as ‘green beryl’, distinct from darker green ‘emeralds’. However, in practice, almost all green beryls are referred to as emeralds within the jewellery trade. Only very pale green beryls with very low saturation are likely to be described in this way.

Emerald is as synonyms with the colour green as rubies are with red and sapphires with blue. Despite this fact, the mineral that emeralds are made out of, 'beryl', can actually come in many colours, much like corundum, the mineral that makes up rubies and sapphires, do too. From the Emerald City to the Emerald Isle, the name emerald is firmly engrained in the minds of many as denoting something green. Find out more about the various colours of beryl here.

Emerald mining

The first known mining of Emeralds was in Egypt and in the 14th Century and today there are Emerald mines in Africa, South America and Asia.

Emerald Colour

As with all coloured stones, emeralds are graded primarily on their colour, though the size and clarity have an effect on their value too. The depth and intensity of the colour, as well the exact shade of green, have the largest effect on the value of the stone.

The green colour in emeralds is primarily caused by the presence of chromium in the atom structure of the stone. This being said, vanadium can also help to influence the colour, especially in stones from Brazil.

The most valuable emeralds will often have a slight blue hint or tinge. The blue tinge is caused by iron and the exact hue is determined by the oxidisation of the iron.

Emerald clarity

Cut and polished emeralds will almost always have inclusions, often large and clearly visible. This is rare for coloured gemstones as, with most varieties, only the best rough crystals with the fewest natural inclusions are faceted. Even the other popular types of beryl, aquamarine and morganite, are rarely cut with prominent, visible inclusions.

Emeralds without inclusions and with good colour are very rare and highly sought after. Needless to say, these stones can fetch very high prices.

Emeralds with visible inclusions are cut and facetedd because of the rarity of the stone and because emeralds are sought after because of their colour, rather than their sparkle, which would be affected by inclusions.

Emerald cut

Beryl crystals grow in a long, hexagonal shape which is why many emeralds are cut in a rectangular shape, known as an ‘Emerald cut’. This type of cut helps to get the biggest possible yield from a rough crystal.

Where do Emeralds come from?

Today, Columbia is the most famous location for emerald mining, though they are found in many places. Pakistan, Afghanistan, Zambia, Brazil, and Russia are all important sources, producing thousands of cts annually. In the past, India was a source of emeralds.

Chivor in Colombia is famous for its Emerald mine.

How hard are Emeralds?

Emeralds measure 7 on the Mohs scale of mineral hardness, which means they are suitable for all but the most often worn items of jewellery.

This being said, some people do wear emerald engagement rings, but special care must be taken and over time the stone will show signs of wear.

Emeralds are perfect for items of jewellery that don’t come into contact with surfaces, like earrings and necklaces.

Caring for emeralds

Emeralds have some unique natural properties that mean you need to take a little extra care with them. It's a good idea not to store them with jewellery that contains harder gemstones like diamonds, sapphires, or rubies, as these stones might scratch emeralds.

You also can’t clean emeralds in an ultrasonic cleaner because many of them are oiled. The process of oil filling helps to fill fissures, however, the continual vibrations and some of the elements in the cleaning solution dissolve or dislodge the oil. This can lead to stones breaking apart in extreme cases.

Emerald birthstone

Emerald is the birthstone for the month of May.