If you were born in July, you probably know you’re “supposed” to love ruby. If you’re a September baby, sapphire gets assigned to you whether you asked for it or not.
But who decided that?
Who sat down and declared that March belongs to aquamarine? And when did the entire jewelry world agree to follow the same list?
The answer starts in the ancient world… wanders through astrology and medieval superstition… and eventually lands in a 1912 jewelry industry meeting.
Let’s pull the thread.
The Ancient Beginning: Twelve Stones, One Sacred Breastplate
The earliest known origin of birthstones appears in the Book of Exodus in the Hebrew Bible.
The High Priest Aaron wore a ceremonial breastplate set with twelve gemstones, each representing one of the twelve tribes of Israel. These stones were not originally assigned to months. They were symbolic — tribal, spiritual, sacred.
Later scholars, including the first-century historian Josephus, connected those twelve stones to the twelve zodiac signs. Over time, the zodiac signs became linked to the twelve months of the year.
But here’s the key detail most people miss:
Originally, people didn’t wear one stone based on their birth month.
They wore all twelve. (These days we might say "that's a bit much")
The belief was that wearing the full set allowed access to the complete spectrum of spiritual power. It wasn’t about individuality. It was about carrying the entire cosmic toolkit.
The idea of “your personal stone” came later.
Astrology, Planets, and Protective Power
By the early centuries of the Common Era, gemstones were widely believed to hold metaphysical properties. Different stones were associated with different planets. Planets were associated with different zodiac signs. Zodiac signs were associated with months.
But there was no universal agreement.
Lists varied wildly by region and culture. The gemstone assigned to March in one part of Europe might be completely different somewhere else. There was symbolism, but no standardization.
In medieval Europe, gemstones were believed to:
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Protect against illness
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Guard against poison
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Shift color to signal danger
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Amplify divine or planetary energy
Birthstones weren’t fashion. They were spiritual technology.
The 1912 Standardization: Enter the Jewelers
Fast-forward to 1912.
The National Association of Jewelers in the United States (now Jewelers of America) officially standardized the modern birthstone list.
Why?
Because consistency makes commerce easier.
If jewelers across the country are selling different stones for the same month, it creates confusion. A single, agreed-upon list simplified marketing, inventory, and consumer expectations.
Additional updates were made later — in 1952, 2002, and 2016 — adding alternative birthstones like tanzanite and spinel.
So today’s birthstone chart is a blend of:
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Biblical symbolism
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Astrological tradition
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Medieval lore
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And a very practical 20th-century industry decision
Ancient mysticism and modern marketing, shaking hands.
The Modern Birthstone List
Here is the current standard birthstone chart recognized in the United States:
Multiple options now exist for several months, partly because of availability, partly because of supply realities, and partly because consumers enjoy choice.
And honestly? Choice is very modern.
Why Birthstones Still Matter
Here’s the real reason birthstones have survived thousands of years.
They anchor beauty to identity.
They give us a story. A timestamp. A way to say:
“This is mine.”
They mark birthdays, anniversaries, births of children, personal milestones, reinventions, survivals.
Whether you’re drawn to aquamarine for its cool clarity or emerald for its depth and saturation, birthstones create a built-in narrative.
And jewelry becomes more meaningful when it carries context.
The original tradition may have been cosmic protection.
Today, it’s personal symbolism.
But the through-line is the same: We want objects that mean something.
