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Emerald: the May birthstone

Loose emeralds

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Every month of the year has a birthstone, and for those lucky enough to have been born in May, their birthstone is the gorgeous green emerald. This means that if you're looking for an engagement ring and you or your partner were born in May, a great place to start would be to browse some of our emerald engagement rings for inspiration.

The May birthstone is a member of the beryl family of gems, which also includes aquamarine and morganite, and is a highly captivating gemstone with some unique properties. In this article, we'll explore the appearance and characteristics of emeralds, where they're found, their history and meaning, and how to look after them.

Appearance and characteristics of emeralds

Emerald cut emerald
Vivid green emerald cut emerald with visible natural inclusions

The finest emeralds are pure green or green with a hint of blue

When examining an emerald, colour is the most important quality factor, and subtle colour variations can result in significant differences in value.

The colour of an emerald is determined by trace elements of vanadium, chromium and iron within the crystal and defined in terms of its hue, saturation and tone: 

  • Hue refers to the shade of green; for example, it might contain a faint hint of yellow or blue. Generally, pure green or a faint hint of blue are considered the most desirable hues. 
  • Saturation refers to how intense the colour is; the more intense, the better. 
  • Tone refers to how light or dark the stone is, with a medium tone (not too dark) generally considered the best.

Colour distribution with an emerald is also important. Ideally, it should be evenly distributed, with no noticeable "zoning" (variation in hue, saturation or tone).

Emerald selection
Emeralds in a range of shapes, colours and clarities

Flawless emeralds are extremely rare

Nearly every emerald has some visible blemishes or 'inclusions' caused by mineral impurities, tiny fractures, or growth lines in the crystal, varying from the barely perceptible to the very pronounced.

Emeralds that are completely free of inclusions are extremely rare and exceptionally valuable. Carat for carat, the best emeralds can be twice as valuable as a diamond. So, depending on your budget, if the idea of a gemstone not looking completely flawless bothers you, an emerald may not be your best option!

In the trade, emerald inclusions are called "jardin" (from the French for garden) and sometimes are described as looking "mossy" or "garden-like". Whilst it is accepted that most emeralds have visible inclusions if the inclusions are so pronounced that they compromise the transparency of the gemstone, then its value is significantly reduced.

How an emerald is cut impacts its colour and clarity

A good emerald cutter will aim to cut an emerald in a way that optimises the colour hue, tone and saturation while simultaneously minimising the visibility of inclusions.

uncut emeralds
Rough emerald crystals - note their elongated shape

By orienting the table facet (the flat top of the emerald) so that it is perpendicular to the length of the rough emerald crystal, a cutter can maximise the blue-green hue that is so highly prized, and by cutting a stone with deep proportions, a small table and fewer facets, they can darken it. Likewise, they can make it brighter by cutting a stone with shallower proportions, a large table, and more facets.

As the name suggests, the emerald cut (rectangular with the corners removed, so strictly speaking octagonal, and with stepped rather than brilliant faceting) was developed for emeralds and remains to this day the most popular cut for the May birthstone.

Emeralds are often treated to improve their appearance

As with any gemstone, before buying an emerald, you should check whether it has been subjected to any treatment. Treatments are often used to enhance an emerald's appearance and are not necessarily a problem so long as they have been disclosed and you understand their implications.

Many emeralds are oiled to improve their colour and clarity, and even an emerald that has not been actively oiled is likely to have been exposed to minor traces of oil from the cutting wheel on which it was faceted. Over time the oil may dry out, making any inclusions more visible and the stone's colour less vibrant. If that happens, the emerald's former appearance can be restored by re-oiling it — a simple and inexpensive process. Sometimes coloured oils and dyes are used, but these can fade if the stone is exposed to strong light. Alternatively, some emeralds have their surface-reaching inclusions filled with glass or resin to improve their appearance, but this can leave these stones in an unstable condition, vulnerable to changes in air pressure, heat, and various chemicals. We would recommend steering clear of dyed stones or ones that have been treated with glass or resin.

If you have any concerns about whether an emerald has been treated, you should consider having it examined by an independent gemologist. An emerald report from the GIA will grade any treatment as minor, moderate or significant enhancement.

Emerald is a relatively soft gemstone

Any piece of jewellery can be damaged through wear and tear, but if you've got your heart set on an emerald engagement ring, please be aware that you'll need to be extra careful with it. Emerald is not a very hard gemstone, scoring 7.5-8.0 on the Mohs hardness scale, compared with 9 for sapphire and ruby (at least ten times harder) and 10 for diamond (ten times harder still).

An emerald's inclusions are its natural weak spots, so if you bump your ring against something hard, you can cause inclusions to become more visible or even damage the stone more severely. Its comparative softness also needs to be taken into consideration when setting an emerald. Platinum is less malleable than gold and needs more force applied when setting a stone – a setter will need to take extra care when setting an emerald in platinum.

The history and meaning of emeralds

Emeralds have been cherished for thousands of years

The word "emerald" comes from "smaragdos", ancient Greek for "green gem", and the May birthstone has been prized for its beauty and scarcity for thousands of years. Indeed, historical records show that emeralds were sold in markets in Babylon as early as 4000 BC, and according to the old testament of the bible, an emerald was one of the precious gems given by God to King Solomon, giving him power over all creation!

The earliest recorded emerald mining took place in ancient Egypt about 2000 years ago. Cleopatra herself is known to have adored the luscious green gemstone, and at about the same time, in ancient Rome, Pliny the Elder wrote in his encyclopaedic Natural History that "nothing greens greener." He also believed that the May birthstone had therapeutic properties, claiming that:

“[gem cutters] have no better method of restoring their eyes than by looking at the emerald, its soft, green colour comforting and removing their weariness and lassitude.”

Pliny the Elder

Hundreds of years later, though still more than 500 years ago, the Incan emperors of South America also had a passion for emeralds. The legendary Crown of the Andes, fashioned by the Spanish conquistadors, includes a 24ct emerald taken from the last Incan emperor, Atahualpa, as well as a further 442 smaller emeralds.

Emeralds are associated with nature and springtime and are said to hold many talismanic properties

Evoking the lush greens of nature, emeralds are associated with new spring growth, making them the perfect choice of birthstone for the month of May. 

Moreover, in legend and folklore, the May birthstone is believed to hold many special powers. Some believed that an emerald placed under the tongue allowed you to see into the future, while others thought that wearing an emerald made you more intelligent; exposed the lies of lovers; protected against evil spells; or even cured diseases including cholera and malaria.

How to care for an emerald

Being relatively soft gemstones, emeralds need to be treated with extra care. They can be scratched or chipped more easily than diamonds, sapphires or rubies, for example, so more consideration needs to be given to how emeralds are set within jewellery and how and when emerald jewellery is worn.

Emerald ring
A rub-over setting protects the edges of this cushion cut emerald

In terms of settings, it is best to avoid designs that expose an emerald's vulnerable edges and corners to possible chipping. The most protective setting method is a rub-over or bezel setting (as seen in the emerald ring above), where the entire edge of the stone is protected by metal.

However an emerald has been set, it is best to avoid wearing emerald jewellery whenever there is an increased chance of it being damaged, such as during exercise or manual tasks. We strongly recommend removing and storing your emerald ring safely at such times.

Extra special care needs to be taken when cleaning emerald jewellery, not only because emeralds are soft and therefore easily scratched and chipped, but also because many emeralds are oiled to enhance their appearance, and cleaning an emerald can remove the oil, resulting in the emerald's appearance changing (often looking less vivid in colour, and with inclusions becoming more visible). You should avoid exposing an emerald to hot water, for example, while washing your hands.

Although it is relatively easy to re-oil an emerald by carefully wiping it with a colourless baby oil, cleaning emerald jewellery and re-oiling emeralds is best left to a professional jeweller.


Are emeralds expensive?

All else being equal, emeralds are generally less expensive than diamonds or rubies but more expensive than sapphires. That said, as with all gems, the prices of emeralds vary considerably based on their size (carat weight) and quality (colour and clarity). All else being equal, a larger emerald is more valuable than a smaller emerald, and prices increase exponentially with size. This means that an emerald that is twice as big will be more than twice as expensive, assuming the same quality.

In terms of quality, the most prized colour is intense pure green (or green with a faint hint of blue) with a medium tone (not too dark). The more the colour deviates from this ideal, the lower the value. Likewise, ideally, an emerald would have flawless clarity, but emeralds that are completely free of inclusions are extremely rare and exceptionally valuable.

Can emeralds be lab-grown?

Yes, scientists have been able to create emeralds in the lab since the 1930s, and there are several different techniques in use today. An emerald is the variety of the mineral beryl, and the most widely used method for growing gem-quality emeralds commercially starts with beryl in a colourless form, which turns green through the addition of chromium oxide.

There is absolutely nothing wrong with purchasing a lab-grown emerald. Still, since they are much less valuable than natural emeralds, anyone selling a lab-grown emerald must disclose it as such rather than trying to pass it off as a natural gemstone. If you are purchasing an emerald and are in any doubt about whether the gemstone in question is natural or lab-grown, you should ask for an independent gemological report to verify its status.

Where are emeralds found?

Most emeralds today are mined in Zambia and Colombia, but emeralds are also found in many other countries. Zambia is the biggest exporter of emeralds in the world, and Colombia is the source of the highest quality emeralds, prized for their rich green colour. However, emeralds are also mined in Brazil, Afghanistan, Ethiopia, Australia, Pakistan, Russia and the USA.


Emerald is the May birthstone and has been prized since antiquity for its beautiful appearance and scarcity. Although all emeralds are green, the hue, tone and saturation vary from one emerald to another, with the most highly sought-after colours being intense pure green (or green with a faint hint of blue) with a medium tone (not too dark). Very few emeralds are "eye clean", and those that are flawless trade at a very significant premium. Many emeralds are treated to enhance their clarity and colour, and any such treatment must be disclosed since it significantly impacts value. Finally, it is essential to treat emeralds with care since they are relatively soft gemstones, meaning they can be scratched or chipped more easily than diamonds, sapphires or rubies, for example.

Tim Ingle
Together with David Rhode, Tim created Ingle & Rhode to offer a better alternative to the traditional luxury brands. Since 2007, we’ve provided our customers with genuinely ethical engagement rings, wedding rings and fine jewellery – free from conflict diamonds, dirty gold and child labour. With more than 16 years experience in the jewellery industry, Tim has deep expertise in diamonds, gemstones and jewellery design and manufacturing.