Birthstones by Month: The Chart, and Who Decided It

Birthstones by month: the full chart

Three columns, because three answers are in circulation. The first is what a US jeweller will sell you today; the second is the list usually labelled "traditional", which predates 1912 and varies by source; the third is the dominant colour, which is what most people actually choose by.

Month	Modern (US trade)	Commonly called traditional	Colour
January	Garnet	Garnet	Deep red
February	Amethyst	Amethyst	Purple
March	Aquamarine, bloodstone	Bloodstone	Pale blue-green
April	Diamond	Diamond	Colourless
May	Emerald	Emerald	Green
June	Pearl, moonstone, alexandrite	Pearl	White to colour-change
July	Ruby	Ruby	Red
August	Peridot, spinel, sardonyx	Sardonyx	Olive green
September	Sapphire	Sapphire	Blue
October	Opal, tourmaline	Tourmaline	Iridescent, or any
November	Topaz, citrine	Citrine	Golden yellow
December	Turquoise, zircon, tanzanite, blue topaz	Turquoise or lapis lazuli	Blue

If another site gave you a different stone, it is not necessarily wrong. It is quoting a different revision or a different country's list, and almost none of them say which.

Who actually decided this, and when

The list has a paper trail, and it is short enough to give in full.

Four revisions in a century, each made by a trade body, each expanding the number of stones a customer might reasonably buy. That is not a conspiracy — and one addition, spinel, corrected a genuine injustice, since spinel spent centuries being sold as ruby and some famous "rubies" in royal collections are spinel.

But it does settle one question. Nobody inherited this. It was decided, in living memory, by people in the business of selling stones.

Where the idea came from before 1912

The 1912 meeting did not invent the idea of a stone for a month; it standardised something already loose in circulation. The chain is traceable, and stranger than the charts suggest.

It begins with the breastplate described in Exodus 28, set with twelve stones for the twelve tribes of Israel. In the first century the historian Josephus drew a connection between those twelve stones, the twelve months and the twelve signs of the zodiac. St Jerome, some three centuries later, repeated a version of the association. Neither of them was describing a birthstone in the modern sense — the idea that you own one stone, the one for your own birth month, rather than wearing all twelve in turn, appears much later, and is often attributed to Poland in the eighteenth century, though the evidence for that specific claim is thin.

The person who did most to fix the story in the modern mind was George Frederick Kunz, Tiffany's gemmologist, whose The Curious Lore of Precious Stones appeared in 1913 — one year after the list was standardised. Most of the history on jewellery sites traces back to Kunz, usually at several removes and without attribution. He was a serious scholar; he also worked for a jeweller, and his book came out the year after the trade agreed the list it explained.

One problem undermines the whole lineage: the Hebrew names of the breastplate stones cannot be reliably matched to modern mineral species, and scholars disagree about nearly all twelve. "Sapphire" in the ancient sources most likely meant lapis lazuli. The chain runs from a set of stones nobody can identify, through two ancient writers making an astrological association, to a trade meeting in Missouri.

Traditional versus modern: what actually changed

"Traditional" is doing a lot of unearned work on most charts. There is no single traditional list. What circulates under that name is generally a pre-1912 English or American set, and different sources reconstruct it differently. The differences that matter in practice are these.

• March. Bloodstone was the older stone; aquamarine displaced it. Bloodstone is a dark green chalcedony flecked with red and looks nothing like aquamarine, so this is the largest visual change on the chart.
• August. Sardonyx was the older stone; peridot took the primary position, and spinel joined in 2016. Three stones, three entirely different colours.
• November. Topaz and citrine sit side by side, and because most commercial citrine is heat-treated amethyst, a great many November birthstones began life as February's.
• December. The most crowded month, with four stones in current circulation. Lapis lazuli appears on older lists and has quietly dropped off most modern ones.
• June. Pearl is the old answer, moonstone the practical one and alexandrite the expensive one. More on that below, because June is where the gap between the chart and the shop is widest.

Birthstone or zodiac stone — they are not the same thing

This is the single most common confusion, and it has a mechanical cause. Birthstones follow calendar months, which begin on the first. Zodiac signs begin around the twenty-first. So anyone born in the first three weeks of a month has a birthstone from one list and a zodiac stone from a sign that started the month before.

Zodiac stone lists are also older, less standardised and far more varied, coming from astrological and lapidary traditions rather than a trade body. If a site gives you one confident zodiac stone per sign, it has chosen a tradition and not told you.

Neither list is the "real" one. They answer different questions: one is keyed to the civil calendar, the other to the position of the sun. If you want a stone to wear, pick by whichever frame you actually use, or by colour, which is what most people do anyway.

What you are actually buying, month by month

This is the section the jewellery sites cannot write comfortably, and it is the practical heart of the article. Almost every stone on the modern list reaches the counter having been altered, cultured or grown, and for most of them that is entirely normal and disclosed. It is only a problem when nobody tells you.

Stone	What is usual in the trade	What to ask
Blue topaz (Dec)	Effectively all of it is irradiated and then heated. Natural blue topaz is pale and uncommon; sky, Swiss and London blue are treatment names, not localities.	Nothing, really — assume treated. Be suspicious of anyone selling "natural blue topaz" at a normal price.
Citrine (Nov)	Most commercial citrine is amethyst that has been heated until it turns golden. Natural citrine exists and is usually paler and smokier.	"Is this heat-treated amethyst or natural citrine?" A straight answer is a good sign about the seller.
Alexandrite (Jun)	The colour change is entirely natural and needs no treatment — but natural gem-quality alexandrite is among the rarest stones on the list and priced accordingly. Affordable "alexandrite" is usually lab-grown, or a colour-change corundum standing in for it.	"Natural, lab-grown, or simulant?" Three different things at three very different prices.
Pearl (Jun)	Essentially every pearl sold today is cultured. Natural pearls are auction-house material.	Freshwater or saltwater, and whether it has been dyed.
Emerald (May)	Filling of surface-reaching fissures with oil or resin is close to universal and accepted practice.	What the filler is, and whether it needs care avoiding heat and solvents.
Ruby, sapphire (Jul, Sep)	Routine heat treatment to improve colour and clarity, long-established and normally disclosed. Untreated stones carry a premium.	Heated or unheated, and whether there is a lab report if the price implies unheated.
Turquoise (Dec)	Frequently stabilised with resin, because most turquoise is too porous to cut otherwise. Dyeing and reconstitution also occur.	Natural, stabilised, or reconstituted — the price gap between them is large.
Opal (Oct)	Inexpensive opal jewellery is often a doublet or triplet — a thin slice backed and sometimes capped — rather than a solid stone.	"Solid, doublet or triplet?" It changes how you can clean and wear it.

None of this makes a stone fake. A lab-grown alexandrite is chemically and optically alexandrite; irradiated blue topaz is topaz. The distinction that matters is disclosure, and our longer piece on real versus treated crystals goes through how to tell, for the stones where it is possible to tell by eye.

The colours, since that is what most people choose by

Ask someone what their birthstone is and they will usually name a colour before they name a mineral. Here is the chart as colour, which is also the most useful version if you are buying a gift and do not know the recipient's taste in stones.

Two months are awkward as colour. April is colourless, which is why clear quartz and white topaz stand in so often; October is iridescent rather than any one hue, which is why its alternate tourmaline — a mineral that comes in essentially every colour there is — gets used instead.

The "mystical" and "Ayurvedic" lists, and what we could not verify

Alongside the modern and traditional charts you will meet two others, and we want to be straight about the limits of what we could establish.

The mystical list is described almost everywhere as Tibetan and more than a thousand years old. We were not able to find a primary source for that claim — no manuscript, no scholarly citation, no named text. What we found was the claim itself, repeated across jewellery sites in near-identical wording. There is also a structural problem with it: the Tibetan calendar is lunisolar and its months do not line up with January through December, so a clean twelve-month Gregorian mapping is anachronistic on its face. That does not prove the list is a modern invention. It does mean that anyone stating its age with confidence is repeating something they have not checked, and we are not going to join them.

The Ayurvedic list has firmer footing: Jyotisha, Indian astrology, genuinely does assign gemstones — but by planetary position in an individual chart, not by birth month. A twelve-row month chart labelled "Ayurvedic birthstones" has already flattened the system it claims to represent.

Both are out of the main table for that reason: listing them beside a documented 1912 trade decision would imply a parity of evidence that does not exist.

Which birthstones are genuinely rare

Rarity and price are not the same thing, and neither tracks the chart. Diamond is April's stone and is not, geologically, a rare mineral; its price reflects a supply chain and a century of marketing. Alexandrite and natural pearl are genuinely rare, and tanzanite comes from a single small area in Tanzania — often called rarer than diamond, which is true in the narrow sense of total known deposit.

At the other end, amethyst, garnet, peridot, citrine and blue topaz are all abundant and inexpensive, which is precisely why they are pleasant to own.

Can you wear a birthstone that isn't yours?

Yes. There is no rule against it, no tradition that forbids it, and no source that says otherwise — this is one of those questions where the honest answer is shorter than people expect.

The worry comes from a sense that the stone is "assigned", which the history above settles: it was assigned in 1912, by a committee, for commercial convenience. Wearing September's sapphire when you were born in March breaks nothing.

Are birthstones pagan, biblical, or neither?

All three answers are in the autocomplete, so here is each one honestly.

Biblical in ancestry, at a stretch: the lineage runs back to the Exodus breastplate, though that was a priestly vestment for twelve tribes, not a personal amulet for a birth month, and the stone identifications are unreliable.

Pagan, in the sense the question usually intends — that is, occult or astrological — only through Josephus's zodiac association and the later lapidary tradition. The month list itself carries no ritual instruction and no deity.

Neither, in practice. The list you will be sold is a twentieth-century American retail standard. Whether you then use a stone devotionally is a separate decision, and people from every religious position and none wear them without difficulty. If you want to work with a stone deliberately rather than decoratively, the framework most people find useful is intention rather than birth date — our guide to choosing a crystal by what you are working on takes that route instead.

Try it: which stone are you actually looking for?

Voices from practice

Recurring themes from people who sell, gift and wear these stones, paraphrased rather than quoted, since none of them asked to be named:

• The commonest disappointment is December. Someone is given turquoise, having expected the blue topaz they saw online, or the reverse.
• Almost nobody told the 1912 story stops caring about their birthstone. Most find it more interesting, not less.
• June causes the most returns, because "alexandrite" at a low price is rarely what the buyer pictured.
• The question asked more often than any other in a shop is not about meaning. It is "is this the real one".

What we don't promise

• We make no claim that any stone influences health, mood, luck, money or relationships. Stones are beautiful and they are good to think with; that is the whole of what we will say for them.
• The 1912, 1952, 2002 and 2016 revisions are documented trade decisions. The pre-1912 history is genuinely contested, and we have said where the evidence thins out rather than smoothing it over.
• We could not verify the Tibetan origin claimed for the mystical list, and we are not repeating it as fact.
• Treatment practices described here are what is usual in the trade. Any individual stone can differ, and a reputable seller will tell you which.
• Nothing here is an appraisal or a valuation. If a purchase is significant, ask for an independent laboratory report.

Practically: how to work with this

Decide first whether you want the month's stone or a stone you like, and be honest about it, because the second is a perfectly good answer and most people arrive at it eventually. If it is the month's stone, use the modern US list, since that is what sellers here stock, and check whether the month has alternates before you settle — June, August, October, November and December all do.

Then ask the treatment question. One sentence — "is this treated, and how?" — separates sellers who know their stock from sellers who do not, and the answer costs nothing. After that it is ordinary care: our notes on which stones fade in sunlight matter for amethyst and rose quartz in particular, and how to cleanse a crystal covers the methods that will not damage a porous or treated stone. If you would rather wear it on the wrist than at the neck, which wrist to wear a crystal bracelet on handles that question at more length than it probably deserves.

Our crystals and stones run from tumbled pocket stones upwards, and the necklaces and malas are where most birthstone-shaped requests end up.

Frequently asked questions

Who decided the birthstones for each month?

The National Association of Jewelers, at a meeting in Kansas City in 1912. It was revised by the Jewelry Industry Council of America in 1952, and the American Gem Trade Association added tanzanite to December in 2002 and spinel to August in 2016. Earlier month-and-stone associations existed, but the list sold in the United States today is a twentieth-century trade standard.

What is the difference between traditional and modern birthstones?

The modern list is the current US trade list and gives several months more than one option. "Traditional" refers to pre-1912 sets, which vary by source and country. The largest differences are March (bloodstone rather than aquamarine), August (sardonyx rather than peridot), November (citrine rather than topaz) and December, where lapis lazuli appears on older lists.

Can you wear a birthstone that isn't your own?

Yes. No tradition forbids it and nothing is broken by it. The month list is a retail convention agreed in 1912, not an assignment. Many people wear a stone because they like it, because it was given to them, or because it belongs to someone they love.

What is the rarest birthstone?

Natural alexandrite, June's third stone, is the rarest on the list, followed by natural pearl and tanzanite. Diamond is expensive but not geologically rare. Amethyst, garnet, peridot, citrine and blue topaz are all abundant and inexpensive.

Is my birthstone the same as my zodiac stone?

Usually not. Birthstones follow calendar months starting on the first; zodiac signs begin around the twenty-first. Anyone born in the first three weeks of a month will have a birthstone and a zodiac stone from different periods. Zodiac stone lists are also far less standardised, and no two sources agree on them.

Is blue topaz natural?

The topaz is natural; the blue almost never is. Effectively all commercial blue topaz is irradiated and then heated to produce and fix the colour. Sky blue, Swiss blue and London blue are names for treatment results, not for places. Naturally blue topaz exists but is pale and uncommon.

Are mystical or Tibetan birthstones authentic?

We could not verify the claim. The mystical list is described almost universally as Tibetan and over a thousand years old, but we found no primary source, manuscript or scholarly citation for it — only the claim repeated in near-identical wording. The Tibetan calendar is also lunisolar, so a twelve-month Gregorian chart does not map onto it cleanly.

Sources & further reading

• International Gem Society, History of Birthstones and Birthstone Chart — Modern and Traditional (gemsociety.org).
• National Jeweler, "Rocks On: The Evolution of the Birthstone List", and "JA, AGTA Add Spinel as August Birthstone" (July 2016).
• George Frederick Kunz, The Curious Lore of Precious Stones, Philadelphia and London, 1913 — the source most later accounts draw on, directly or at a remove.
• Exodus 28:17–20 for the breastplate; Flavius Josephus, Antiquities of the Jews III.7 and The Jewish War V.5 for the zodiac association.
• Gemological Institute of America, gem-by-gem treatment and disclosure descriptions (gia.edu), for the treatment table.

Colour swatches are indicative of the dominant hue and not colour-accurate reproductions of any particular stone.