Birthstone by Month: The List, and What It Actually Traces Back To

The modern list — one stone per birth month — was standardized by American jewelers in 1912, though it draws on a folk tradition centuries older and keeps getting revised (spinel joined August in 2016). Diamond (April) and pearl (June) are the only two months that line up with a material Revoulou actually stocks; the rest are historical, not a catalogue.

A stone assigned to your birth month feels like it should be ancient and fixed. It is ancient in origin and anything but fixed — the list has been added to, argued over, and formally revised as recently as 2016. Here is where it actually comes from, and the current list.

Where the idea comes from

The earliest traceable root is the breastplate of Aaron described in the Book of Exodus: twelve gemstones, one for each tribe of Israel, arranged in four rows of three. A first-century historian, Josephus, later connected those twelve stones to the twelve months of the year and the twelve signs of the zodiac — the first written link between a stone and a month, though not yet the list jewelers use today.

The idea of actually wearing your month's stone, rather than just knowing the association, is generally traced to a Polish gem-trading tradition in the 18th century. It caught on as a piece of folklore and stayed loose and regional for the next century and a half — different countries and different jewelers' guilds circulated slightly different lists.

The 1912 list, and what's changed since

The list most people mean by "birthstones" today was standardized in 1912 by the National Association of Jewelers (now Jewelers of America), specifically to settle the regional disagreements and give the trade one list to sell against. It has been revised since — tanzanite was added to December in 2002, and spinel joined August in 2016 — so "the birthstone list" is a living trade document, not a fixed ancient text.

A note on that last one: zircon here means the natural gemstone — a real, colorless-to-blue mineral distinct from cubic zirconia, the synthetic stand-in most people encounter today. We cover that distinction, and why the trade names get confused, in our moissanite/zircon/lab-grown comparison.

Why some months list more than one stone

Almost every addition to the original list happened because a newly popular stone needed a home and a month was chosen for marketing reasons — alexandrite (a 19th-century Russian find) got attached to June alongside pearl, and spinel was added to August in 2016 largely because fine red spinel had spent decades being sold, unknowingly, as ruby, and the trade wanted to give it its own identity. None of the alternates displace the original; they sit alongside it.

What this means for what we actually sell

Being straightforward about it: Revoulou doesn't stock loose sapphires, emeralds, or rubies, so most of this list describes a tradition rather than a page in our shop. Two months are the honest exception. April's stone is diamond, and lab-grown diamond — chemically identical, same hardness, same fire — is in the collection. June's stone is pearl, which is also, straightforwardly, in the collection. If your birth month is April or June, the traditional stone and an actual piece you can buy are the same thing; every other month, treat this as the historical answer, not a catalogue.

A different system, on this site

Birthstone-by-month is a calendar tradition — it only cares which month you were born in. Our Birth Chart tool answers a related but genuinely different question: it looks at your sun sign's classical element (fire, earth, air, water) and recommends a color and material from that. The two systems can point at different stones for the same person, and neither is wrong — they're just answering different questions. We walk through that element-based system, sign by sign, in a companion piece.