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May Birthstone

May's stone is emerald — the green that other greens get measured against. It is beryl, the same mineral family as March's aquamarine, but colored by chromium into a green so distinctive the trade named a color after it. Emerald has been mined for cleopatra-level luxury for over two thousand years, and fine stones still trade at prices that rival or beat diamond, carat for carat.

It is also the birthstone that most needs honest expectations: emeralds are almost never clean. Their internal gardens of inclusions — the French trade calls them jardin — are part of the deal, oiling is standard practice, and knowing both facts is the difference between buying well and buying disappointment. Here's the full picture for May.

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The May birthstone

EmeraldTraditional & modern

The deep-green variety of beryl, colored by chromium (sometimes vanadium) — the same species as aquamarine, transformed by a different trace element. It runs 7.5–8 on the Mohs scale but is brittler than the number suggests, because virtually every emerald is threaded with inclusions and tiny fissures ('jardin'). The benchmark source is Colombia — the Muzo and Chivor mines produce the pure, slightly bluish green the trade prizes most — with Zambia (darker, bluer) and Brazil as the other majors. The step-cut rectangle known as the emerald cut was developed to protect exactly this stone's corners.

What color is the May birthstone?

The May birthstone color is green — specifically 'emerald green,' a vivid, saturated green with a faint blue lean, the shade charts and birthstone jewelry universally use for the month. In the stone itself, color is the overwhelming driver of value: a vividly green stone full of inclusions beats a clean pale one every time.

The range runs yellowish-green (often Brazilian) through the blue-green of Colombia and the darker forest tones of Zambia. Below a certain saturation the trade stops saying 'emerald' at all and calls the stone green beryl — with a price cliff to match.

How May got its birthstone

Egypt mined emeralds near the Red Sea from at least 300 BC — the deposits later romanticized as 'Cleopatra's mines,' since the queen famously claimed the country's emeralds as her own. Rome carried the association of green with renewal and Venus; Pliny wrote that nothing rested the eye like gazing on emerald, and lore long credited the stone with revealing truth and soothing sight.

The modern emerald story begins with the Spanish conquest: the stones flowing from Colombia's Muzo mines in the 1500s stunned Europe and Asia alike — Mughal emperors carved prayer texts into huge Colombian crystals — and Colombia has anchored the top of the market ever since, with Zambia's discoveries in the 20th century adding the second pillar. Emerald has held May on every list, ancient and modern.

Choosing & caring for May birthstones

Buy color first: vivid saturation with medium tone is the whole game, and Colombian-style bluish-green carries the premium. Expect inclusions — eye-visible jardin is normal even in expensive stones, and a suspiciously flawless 'emerald' at a friendly price is synthetic (widely made, honest when disclosed) or green glass. Assume oiling: filling surface-reaching fissures with cedar oil is centuries-old standard practice; labs grade its extent ('minor' to 'significant'), and only resin fillers or undisclosed heavy treatment count as red flags. Practical care: no ultrasonic cleaners ever (they strip oil and can open fissures), protective settings for rings, and re-oiling every few years is routine maintenance, like servicing a watch. Look-alikes: chrome diopside and tsavorite garnet are honest green alternatives; dyed quartz and doublets are the traps.

Frequently asked questions

What is the May birthstone?

Emerald — the chromium-green variety of beryl, on both the traditional and modern lists for as long as lists have existed. Its family sibling is aquamarine, March's stone: same mineral, different trace element.

What color is the May birthstone?

Emerald green — a vivid, saturated green with a slight blue lean. Color is also what the stone's value hangs on: vividness beats clarity, and stones too pale to qualify are sold as green beryl at far lower prices.

Why do emeralds have so many inclusions?

Because of how they grow: chromium-bearing fluids crystallizing in tectonically stressed rock leave nearly every emerald threaded with internal fractures and mineral traces — the 'jardin.' The trade accepts them as part of the stone's identity; clarity expectations that would condemn a diamond are simply wrong for emerald, and a flawless-looking one should raise suspicion, not excitement.

Is an oiled emerald treated or fake?

Treated in the accepted, traditional sense — and almost universal. Cedar oil filled into surface-reaching fissures improves clarity, has been done for centuries, and is graded by labs from 'none' to 'significant' (price scales accordingly). It's maintenance-dependent: ultrasonic cleaners strip it, and periodic re-oiling is normal. Resin fillers and undisclosed heavy treatment are the versions to avoid.

How do I tell emerald from green glass or other green stones?

Glass shows round bubbles under a loupe, warms fast in hand, and lacks emerald's jardin (real inclusions look organic, not bubbly). Tsavorite garnet and chrome diopside are livelier and cleaner but singly refractive or differently toned; peridot is yellower. For any serious price, a lab report answering natural/synthetic/treatment is standard — and worth it, because fine emerald prices rival diamond.

More birthstones

See the full birthstones-by-month chart or jump to April, August, December, February, January, July, June, March, November, October, September.

Last updated 2026-07-19