The birthstone list is one of the stranger artefacts in jewelry. It is part tradition, part marketing, and part genuinely useful buyer's guide — because a stone's hardness, treatment and price vary so wildly across the twelve months that knowing which one you are dealing with tells you almost everything about how to buy it and how to care for it.
This guide covers all twelve months, with the modern stone, the traditional alternatives, and the practical information that matters: how hard the stone is, what treatments are routine and must be disclosed, what a decent example costs per carat, and whether it can survive daily wear.
How the list works
There are effectively three lists in circulation.
The modern list was standardised by the American National Association of Jewelers in 1912 and is what most retailers mean when they say "birthstone." It has been amended several times since — most recently in 2016, when spinel was added for August.
The traditional list predates 1912 and is still used by people who prefer the older associations, particularly for June, August and November.
The mystical list derives from the twelve stones of the breastplate of Aaron described in Exodus, and is the source of most birthstone symbolism. It maps differently from both of the others and is rarely used commercially.
Where the lists disagree, we give all the accepted options and mark which is which. No list is more correct than another — but you should know which one a retailer is quoting, because it sometimes changes the price by a factor of five.
The one thing to know before you buy
Hardness determines where a stone can be worn. Below Mohs 7, a stone will accumulate scratches in a ring worn daily. Below Mohs 6, it will lose its polish. The single most common expensive mistake in birthstone jewelry is setting a soft stone in a ring and wearing it every day.
January — Garnet
Modern: Garnet · Traditional: Garnet · Alternative: None
Mohs hardness: 6.5–7.5 (varies by species)
Routine treatment: None usually; some stones are fracture-filled
Typical price: $30–$300 per carat for fine red; rare colour-change garnets to $1,500+
Garnet is not one mineral but a family, and the differences matter. Almandine is the deep brownish red most commonly sold. Pyrope is a purer red, often brighter. Spessartine is orange, and fine examples are among the most beautiful stones in the trade. Tsavorite is a green grossular garnet that commands emerald-like prices and has better toughness than emerald.
The practical strength of garnet is that it has no cleavage — unlike emerald, it does not split along a plane when struck. That makes it more forgiving than its Mohs rating suggests. The weakness is that the red garnets most people think of are dark and can go nearly black in low light. Buy a garnet in daylight, not under a counter lamp.
Wearability: Good for rings at 7–7.5. Tsavorite at 7.5 is genuinely ring-suitable. Avoid steam cleaning on fracture-filled stones.
February — Amethyst
Modern: Amethyst · Traditional: Amethyst · Alternative: None
Mohs hardness: 7
Routine treatment: Heating (routine and permanent); occasional dyeing
Typical price: $5–$40 per carat; fine untreated Siberian colour to $200+
Amethyst is the most affordable fine-colour stone in the trade, and the reason is abundance. The enormous deposits in Brazil and Zambia mean that a beautiful 10-carat amethyst costs less than a mediocre 1-carat ruby. This is worth knowing before you pay a premium for "rare" amethyst, because there is no such thing at commercial grades.
What does vary enormously is colour. The best amethyst — historically called "Siberian" regardless of origin, and now usually described as "deep Russian" or simply "fine" — is a saturated purple with red flashes and no brown modifier. Commercial amethyst is pale or brownish. The gap between the two is visible across a room, and the price gap is real.
Heating is routine and permanent: most amethyst on the market has been heated to improve colour, and it is not usually disclosed because it is considered standard. Amethyst fades in prolonged direct sunlight — a genuine consideration for a stone worn on a beach holiday.
Wearability: Mohs 7 makes it acceptable for occasional rings and fine for pendants and earrings. It chips at facet edges more easily than its hardness suggests.
March — Aquamarine
Modern: Aquamarine · Traditional: Bloodstone (heliotrope) · Alternative: Aquamarine
Mohs hardness: 7.5–8
Routine treatment: Heating (routine and permanent)
Typical price: $20–$150 per carat; fine unheated Santa Maria colour to $600+
Aquamarine has good hardness, no cleavage, and a colour that flatters almost every skin tone, which makes it one of the most wearable birthstones. The colour range runs from nearly colourless to a deep, slightly greenish blue.
The market has a specific distortion worth understanding: almost all aquamarine is heated, and the heating removes the green component to leave a purer blue. Unheated aquamarine with a strong blue colour is genuinely rare and commands a substantial premium. The term "Santa Maria" originally referred to a specific Brazilian mine and is now used loosely to mean the finest colour regardless of origin — which means it has become a marketing word rather than a location.
Aquamarine is often cut in large sizes because the rough comes in large clean pieces. A 5-carat aquamarine is not remarkable; a 5-carat ruby is.
Wearability: Excellent for rings. Mohs 7.5–8 with no cleavage.
April — Diamond
Modern: Diamond · Traditional: Diamond · Alternative: Sapphire, rock crystal
Mohs hardness: 10
Routine treatment: Laser drilling and fracture filling are common and must be disclosed; HPHT and irradiation change colour
Typical price: Highly variable — see our cut guide
April is the month with the obvious answer, which means the interesting questions are about treatments rather than the stone itself. Clarity-enhanced diamonds — laser-drilled to remove dark inclusions, then fracture-filled to make the drill holes invisible — can cost 30 to 50 percent less than untreated stones of the same grade. They are legitimate, they are commonly sold, and they require disclosure in most jurisdictions. They also cannot be cleaned in an ultrasonic and are difficult to repair if a jeweler heats the stone.
For a full treatment of buying diamond, see our guide to diamond cuts and our comparison of lab-grown and natural stones.
Wearability: The best there is. Mohs 10 with perfect cleavage in four directions — which means it will never scratch, but it can split if struck precisely along a cleavage plane. This is rare but real, and it is why a diamond should never be set in a way that exposes its girdle to direct impact.
May — Emerald
Modern: Emerald · Traditional: Emerald · Alternative: Chrysoprase
Mohs hardness: 7.5–8
Routine treatment: Oiling, resin filling and fracture filling are routine and must be disclosed
Typical price: $200–$3,000 per carat for fine untreated; heavily treated material from $50
Emerald is the most difficult major gemstone to buy honestly, and it is not close.
Nearly every emerald on the market has been clarity-enhanced by filling surface-reaching fractures with a natural or synthetic resin, or with oil. This is accepted trade practice, it is disclosed on reputable laboratory reports, and it is also the single largest source of price variation. An emerald with no filler at all is rare and expensive; one with significant filler can cost a tenth as much and looks similar in a photograph.
The GIA and Gübelin filler scales run from None, F1 (minor), F2 (moderate) to F3 (significant). A retailer quoting a price without stating the filler level is not giving you enough information to judge it.
Structurally, emerald has perfect cleavage — it splits along a plane — and is usually included. That combination makes it genuinely fragile in a ring despite a respectable Mohs number. An emerald ring should be a bezel or a protected setting, should come off before any physical activity, and should never be cleaned in an ultrasonic.
Wearability: Poor for daily-wear rings. Excellent for pendants and earrings.
June — Pearl, Alexandrite and Moonstone
Modern: Pearl, alexandrite, moonstone · Traditional: Pearl · Alternative: Alexandrite
Mohs hardness: Pearl 2.5–4.5 · Alexandrite 8.5 · Moonstone 6–6.5
Routine treatment: Pearl bleaching and dyeing; alexandrite is rarely treated
Typical price: Pearls $10–$10,000+ per strand · Alexandrite $5,000–$50,000+ per carat · Moonstone $10–$200
June is where the birthstone list gets interesting, because the three accepted stones occupy completely different worlds.
Pearl is organic, soft, and destroyed by acids, perfumes and hairspray. It is also the only birthstone that is conventionally strung rather than set, which changes every care rule. A pearl strand should be restrung every two to three years if worn regularly, because the silk stretches and the knots — which prevent one broken thread from scattering every pearl — loosen.
Alexandrite is the rarest stone in this guide and the only one with a genuine supply constraint. It changes colour depending on the light source: green or bluish-green in daylight, red or purplish-red in incandescent light. The effect comes from chromium substituting for aluminium in the crystal lattice, and the strength of the colour change is the primary value driver — far more than clarity. A stone with a weak change is worth a fraction of one with a strong change, at identical size and clarity. Almost all alexandrite on the market is Brazilian, Sri Lankan or Tanzanian; Russian material from the Ural Mountains is effectively unobtainable and priced accordingly.
Moonstone is the affordable option, prized for adularescence — a floating, billowy light that appears to move beneath the surface. It has perfect cleavage in two directions, which makes it genuinely fragile, and a moonstone ring worn daily will develop chips at the edges.
Wearability: Pearl, no. Moonstone, no. Alexandrite, yes — Mohs 8.5 makes it one of the best ring stones available.
July — Ruby
Modern: Ruby · Traditional: Ruby · Alternative: Carnelian
Mohs hardness: 9
Routine treatment: Heating is routine; lead glass filling is common in low-grade material and must be disclosed
Typical price: $500–$15,000+ per carat for fine untreated; glass-filled from $5
Ruby and sapphire are the same mineral — corundum — and the difference is only the trace element that provides colour. Red corundum is ruby; every other colour is sapphire. This matters because it explains why ruby and sapphire share the same excellent durability and the same treatment landscape.
The value determinant in ruby is colour, and specifically a highly saturated, slightly purplish red historically called "pigeon's blood." The term is now used loosely; it originally referred to a specific hue from the Mogok region of Myanmar with a very particular combination of saturation and fluorescence. Burmese origin still carries a premium, though Mozambique and Madagascar now produce excellent material.
The critical buying issue is lead glass filling. Low-grade ruby with many fractures can be filled with lead glass to make it appear clean and transparent. This material is genuinely fragile — it cannot be heated, it is damaged by acids including lemon juice, and it is not repairable. It sells for a few dollars per carat and is sometimes sold as though it were a natural ruby. Any ruby under about $100 per carat should be assumed glass-filled until proven otherwise.
Wearability: Excellent. Mohs 9, no cleavage. One of the two best birthstones for daily ring wear.
August — Peridot and Spinel
Modern: Peridot, spinel · Traditional: Sardonyx · Alternative: Peridot
Mohs hardness: Peridot 6.5–7 · Spinel 7.5–8
Routine treatment: Rarely treated
Typical price: Peridot $20–$200 per carat · Spinel $200–$10,000+ per carat
Peridot is one of the few gemstones that occurs in a single colour — an olive to yellowish green caused by iron — and one of the few that is not routinely treated. It is also one of only two gems known to occur in meteorites, which is a fact worth knowing at a dinner party. Its weakness is a relatively low hardness combined with perfect cleavage, making it prone to both scratching and chipping.
Spinel is the more interesting story. For centuries, spinel was mistaken for ruby — the Black Prince's Ruby in the British Imperial State Crown is a spinel. It was only recognised as a distinct mineral in the nineteenth century, and it has spent most of the time since being undervalued as a result. It is now the most significant undervalued fine gemstone on the market: it has excellent hardness, no cleavage, and in cobalt-blue or vivid pink it rivals anything in the trade at a fraction of the price of comparable ruby or sapphire.
Spinel was added to the modern list for August in 2016. It is the birthstone addition with the strongest practical case, and we would recommend it over peridot for anything worn regularly.
Wearability: Spinel, excellent. Peridot, occasional rings only.
September — Sapphire
Modern: Sapphire · Traditional: Sapphire · Alternative: Lapis lazuli
Mohs hardness: 9
Routine treatment: Heating is routine; beryllium diffusion and lattice diffusion must be disclosed
Typical price: $300–$10,000+ per carat; fine untreated Kashmir to $100,000+
Sapphire is the most versatile birthstone, because it comes in every colour except red — and the colour range is what makes it a genuinely interesting choice rather than a default one. Blue is the classic, but padparadscha (a salmon-pink orange from Sri Lanka) and fancy pink, yellow and green sapphires are all available, often at lower prices than blue.
The value determinant is the usual combination of saturation, tone and origin, with Kashmir blue commanding an enormous premium for a colour described as velvety — a slightly sleepy, soft blue caused by fine rutile inclusions scattering light. Sri Lankan and Madagascan sapphires are brighter and often cleaner, and cost a fraction as much.
The treatment to watch is diffusion. Lattice diffusion introduces beryllium or titanium into a stone at high temperature, changing its colour through the surface layer. A colourless or pale sapphire can be turned into a vivid blue or orange one. This is legitimate when disclosed and fraudulent when not, and it is not always detectable without laboratory analysis. If a sapphire's price is dramatically below market for its apparent colour, diffusion is the first thing to suspect.
Wearability: Excellent. Mohs 9, no cleavage. Along with ruby, the best birthstone for a ring worn every day.
October — Opal and Tourmaline
Modern: Opal, tourmaline · Traditional: Opal · Alternative: Tourmaline
Mohs hardness: Opal 5.5–6.5 · Tourmaline 7–7.5
Routine treatment: Opal is sometimes sugar-acid treated or smoked; tourmaline is routinely heated
Typical price: Opal $50–$5,000+ per carat · Tourmaline $100–$5,000+ per carat
Opal is the most visually extraordinary stone in this guide and the most fragile. Its colour play comes from microscopic silica spheres arranged in a diffraction grating — light is bent into spectral colours by physical structure rather than by absorption, which is why no two opals look alike.
The fragility is real. Opal contains water, typically 3 to 10 percent by weight, and it can craze — develop a network of fine cracks — if it dries out too quickly or is exposed to rapid temperature change. It is also soft enough to scratch with everyday wear and can be damaged by prolonged immersion. An opal should not be worn in the shower, the pool or the sea.
Tourmaline offers the opposite proposition: good hardness, no cleavage, and the widest colour range of any gemstone species, including watermelon tourmaline with a pink core and green rim, and the vivid Paraíba blue caused by copper, which is among the most expensive coloured stones in the world per carat.
Wearability: Tourmaline is acceptable for rings. Opal is not — pendants and earrings only.
November — Topaz and Citrine
Modern: Topaz, citrine · Traditional: Topaz · Alternative: Citrine
Mohs hardness: Topaz 8 · Citrine 7
Routine treatment: Irradiation and heating (blue topaz); citrine is almost always heated amethyst
Typical price: Topaz $10–$200 per carat · Citrine $5–$50 per carat
Topaz is the hardest of the affordable birthstones at Mohs 8, and it comes in a wide range of colours. The most commercially important is blue topaz, which is almost always produced by irradiating colourless material and then heating it. The process is routine, safe and permanent. Two trade names you will see — "Swiss blue" and "London blue" — describe intensity, with London blue the deeper and more valuable.
Natural, untreated blue topaz exists and is rare and expensive. Imperial topaz — a pinkish orange from Brazil — is genuinely rare and priced accordingly.
Topaz has perfect basal cleavage, which means it can split cleanly if struck at the wrong angle. In a ring, that is a real risk. In a pendant, it is not.
Citrine is the affordable alternative, and almost all of it is heat-treated amethyst — the same mineral, with the colour changed by temperature. The two stones are chemically identical; amethyst turns yellow when heated, which is why the price difference between them is smaller than the colour difference suggests. Citrine is durable enough for occasional rings and fine for everything else.
Wearability: Topaz in rings is a moderate risk because of the cleavage. Citrine is acceptable.
December — Turquoise, Zircon and Tanzanite
Modern: Turquoise, zircon, tanzanite · Traditional: Turquoise · Alternative: Lapis lazuli, blue zircon
Mohs hardness: Turquoise 5–6 · Zircon 6.5–7.5 · Tanzanite 6–7
Routine treatment: Turquoise stabilisation and dyeing; tanzanite heating (routine); zircon heating
Typical price: Turquoise $5–$100 per carat · Zircon $20–$300 · Tanzanite $200–$2,000+
Turquoise is soft, porous and almost always treated. Stabilisation — impregnating the stone with resin — is standard practice for most commercial turquoise and is not the same as dyeing, which is deceptive. The best natural material, historically from Sleeping Beauty in Arizona and now largely from Iran, is hard, evenly coloured and untreated, and costs many times more than stabilised stone.
Turquoise should be kept away from perfume, soap and skin oils, all of which discolour it, and it should never be cleaned with anything but a dry cloth.
Zircon is the stone most often confused with cubic zirconia, and they have nothing in common. Zircon is a natural mineral with very high refractive index and strong dispersion, giving it genuine fire. It is also the stone most likely to be metamict — a state where the crystal structure has been damaged by the stone's own radioactive trace elements, leaving it dull and low in specific gravity. Heat treatment repairs this, which is why almost all blue zircon on the market has been heated. Do not confuse zircon with cubic zirconia when a retailer quotes a price.
Tanzanite is the only birthstone with a genuinely finite supply. It occurs in exactly one place on earth — a small area near Mount Kilimanjaro in Tanzania — and no other deposit has ever been found. It is pleochroic, showing different colours in different directions, so it must be cut and oriented carefully to show its best blue-violet face. It is also soft enough that it should not be worn daily, and it is sometimes fracture-filled.
The wearability chart
The most useful thing in this guide is this table. Sort your birthstone by hardness before deciding where it goes on your body.
| Stone |
Mohs |
Cleavage |
Ring, daily |
Ring, occasional |
Pendant / earrings |
| Diamond |
10 |
Perfect (4 directions) |
Yes |
Yes |
Yes |
| Ruby |
9 |
None |
Yes |
Yes |
Yes |
| Sapphire |
9 |
None |
Yes |
Yes |
Yes |
| Alexandrite |
8.5 |
Distinct |
Yes |
Yes |
Yes |
| Topaz |
8 |
Perfect (basal) |
Risky |
Yes |
Yes |
| Aquamarine |
7.5–8 |
None |
Yes |
Yes |
Yes |
| Spinel |
7.5–8 |
None |
Yes |
Yes |
Yes |
| Emerald |
7.5–8 |
Perfect |
No |
Risky |
Yes |
| Tourmaline |
7–7.5 |
None |
Risky |
Yes |
Yes |
| Garnet |
6.5–7.5 |
None |
Risky |
Yes |
Yes |
| Zircon |
6.5–7.5 |
Poor |
Risky |
Yes |
Yes |
| Amethyst |
7 |
None |
Risky |
Yes |
Yes |
| Citrine |
7 |
None |
Risky |
Yes |
Yes |
| Moonstone |
6–6.5 |
Perfect (2 directions) |
No |
Risky |
Yes |
| Peridot |
6.5–7 |
Perfect |
No |
Risky |
Yes |
| Tanzanite |
6–7 |
Perfect |
No |
Risky |
Yes |
| Opal |
5.5–6.5 |
None (but brittle) |
No |
No |
Yes |
| Turquoise |
5–6 |
None |
No |
No |
Yes |
| Pearl |
2.5–4.5 |
None |
No |
No |
Yes |
Frequently asked questions
What are the 12 birthstones by month?
January is garnet, February amethyst, March aquamarine, April diamond, May emerald, June pearl or alexandrite, July ruby, August peridot or spinel, September sapphire, October opal or tourmaline, November topaz or citrine, and December turquoise, zircon or tanzanite.
Which birthstone is the hardest and best for everyday wear?
Diamond, followed by ruby and sapphire, which are both corundum and rate 9 on the Mohs scale. For a birthstone worn daily in a ring, only diamond, ruby, sapphire and chrysoberyl (which includes alexandrite) are genuinely suitable without care. Everything else belongs in earrings, pendants or occasional-wear rings.
Why are there multiple birthstones for some months?
The modern list was standardised by the American National Association of Jewelers in 1912, but it was built on top of older traditional and mystical lists that had already diverged. Later additions — spinel for August in 2016, for instance — were made to give buyers alternatives. The result is that several months now have three accepted stones.
Are birthstones a good investment?
No, with rare exceptions. Birthstone jewelry is bought for meaning rather than value, and most birthstones are widely available. The exceptions are untreated, high-quality alexandrite and fine tanzanite, both of which have genuine supply constraints. A birthstone ring should be bought because it means something, not because it will appreciate.
Can I wear my birthstone every day?
It depends entirely on hardness. Diamond, ruby and sapphire are fine in daily-wear rings. Amethyst, aquamarine, emerald, opal, peridot, topaz, turquoise and pearl all scratch, chip or fracture more easily and should be worn in pendants, earrings or rings reserved for lighter wear.
The bottom line
If you are buying a birthstone for a ring that will be worn daily, the honest shortlist is diamond, ruby, sapphire, alexandrite and spinel. Everything else is better placed in a pendant or a pair of earrings, where it will look the same and last indefinitely.
If you are buying for meaning rather than wear, buy the stone you actually like rather than the one with the best specifications, and buy it in daylight. Birthstone jewelry is one of the few categories in this trade where the correct answer is genuinely personal — and one of the few where you can spend $200 and get something beautiful rather than something compromised.
