The History of Birthstones: Why Does Each Month Have a Specific Gemstone? The Ancient Origins and Meanings You Never Knew.

Birthstones feel like an old, simple idea: a single gem tied to the month you were born. In reality the story is tangled. The list we use today grew from ancient religion, lost translations, medieval gemstone lore, trade routes and modern marketing. Each step changed which stone stood for a month — and why. Below I trace the major turning points and explain how certain gems became attached to specific months.

Where the idea began: 12 stones, 12 powers

The earliest clear ancestor is the ancient Near East. Mesopotamian and later Jewish sources grouped gemstones into sets of twelve. The most famous is the Hebrew “Breastplate of Aaron” (the Hoshen), a religious breastplate described in Exodus with twelve stones, each representing an Israelite tribe. That breastplate was not a monthly calendar, but the number twelve naturally linked to the lunar months and the zodiac — a pairing seen across ancient cultures.

From Babylonian astrology to Hellenistic Egypt, scholars associated stones with planets and constellations. When authors like Pliny and later medieval lapidaries (books about stones) described gems, they often gave each stone powers: protection in battle, healing traits, fertility, clarity of mind. Over centuries those symbolic uses began to be read as seasonal or monthly correspondences.

Translation problems: the same names don’t mean the same gem

One reason the original meaning is confused: ancient names rarely map cleanly to modern gem names. The Hebrew list uses words like odem, tarshish and bareketh. Were these garnet, jasper, emerald, topaz, or something else? Translators relied on Greek and Latin authors who themselves used local names for similar-looking stones.

Example: the Hebrew odem is often translated as “ruby” or “carbuncle,” but it could also mean red garnet. The Greek word smaragdos became “emerald,” but sometimes described green gems we would now call chromian diopside or green tourmaline. Those translation shifts changed which modern gem we associate with a given ancient position.

Medieval lapidaries and the growth of meanings

In the Middle Ages, lapidaries compiled earlier sources and added Christian overlays. Authors tied stones to apostles or virtues. Because most people didn’t distinguish mineral species the way modern gemology does, the same listed “emerald” could be several green stones. Lapidaries also emphasized amuletic uses: sapphires to cure melancholy, amethysts for sobriety, pearls for chastity.

This period cemented the idea that individual gems carried moral or protective properties. Those moral qualities later helped jewelry makers market birthstones as tokens that conveyed character or brought luck.

Modern standardization: the jewelry trade steps in

By the 19th century jewelers and gem dealers were selling jewelry by month to appeal to sentimental buyers. Multiple competing lists existed. In the early 20th century jewelers’ associations in the United States and Britain moved to standardize a single list for mass retail. The result was a widely adopted “modern” birthstone list used by many jewelers worldwide.

Two practical forces shaped that list:

• Availability. Common, attractive stones like garnet, amethyst and sapphire were affordable and easy to source for mass production.
• Marketing. Adding alternate stones (for example, multiple stones for June or December) let stores offer price points from costume to fine jewelry.

Why particular stones for certain months? Brief meanings and practical reasons

Below are common associations and the reasons behind them.

• January — Garnet: Deep red stones historically associated with protection and safe passage. Garnet is durable (6.5–7.5 Mohs) and widely available in sizes from 0.25–5+ ct at reasonable prices.
• February — Amethyst: Name means “not drunk” in Greek. It was prized for color and clarity; now available as 0.50–3 ct stones for rings and pendants.
• March — Aquamarine: Linked to sailors and the sea. Beryl family (emerald is also beryl) with hardness around 7.5–8. Fine aquamarine is often cut 0.5–5 ct to show its blue.
• April — Diamond: Hardness 10 Mohs, symbol of endurance and clarity. Diamonds became linked to engagements and high-value birthstone pieces.
• May — Emerald: Associated with fertility and Venus. Emeralds are beryl (7.5–8 Mohs) but commonly included with natural fractures; protective settings and lower daily-wear sizes are recommended.
• June — Pearl / Alexandrite / Moonstone: Tradition keeps pearls for purity; alexandrite was later offered as a dramatic color-change luxury alternative; moonstone reflects lunar symbolism.
• July — Ruby: Corundum family (9 Mohs), red for passion and power. Rubies are often set in 0.5–3 ct sizes for center stones.
• August — Peridot / Spinel: Peridot (olivine) often appears in lighter green shades; historically linked to the harvest. Spinel and sardonyx appear as traditional alternatives.
• September — Sapphire: Blue sapphire (corundum, 9 Mohs) is associated with wisdom and fidelity. Its durability makes it popular for daily-wear rings.
• October — Opal / Tourmaline: Opal shows play of color and was thought to possess all virtues. Tourmaline offers a wide color range, allowing accessible alternatives.
• November — Topaz / Citrine: Topaz historically symbolized strength; citrine (yellow quartz) is an affordable, bright alternative.
• December — Turquoise / Tanzanite / Zircon: Turquoise was prized in many cultures; tanzanite and blue zircon are modern additions for a blue December palette.

Why some months have more than one stone

Multiple stones serve practical and cultural needs. Different cultures kept their own traditions. New gem discoveries (like tanzanite) led to additions. Jewelers also wanted options at various price points. That’s why June has pearl and alexandrite, and December has three popular choices.

Practical notes: durability, metal choices and sizing

When choosing a birthstone, match the gem to how the piece will be worn.

• Durability: Use hard stones for everyday rings — corundum (sapphire/ruby, 9 Mohs) and diamond. Softer gems like opal (5.5–6.5) or pearl (2.5–4.5) are better for pendants and earrings.
• Settings and metals: For emeralds and other included gems, protective bezel or halo settings reduce chip risk. Use 14k or 18k gold (58–75% Au) or platinum for durability and to reduce wear on prongs.
• Typical sizes: Birthstone center stones commonly range from 0.25–2 ct for pendants and rings. Pearls are measured in mm — common sizes are 6–9 mm for everyday wear, 10–12 mm for dressy pieces.

Conclusion: a mix of ritual, error and commerce

Birthstones are not a single, ancient decree. They evolved from religious sets, through imperfect translation and symbolic medieval lore, into standardized lists shaped by trade and taste. The result is flexible. Choose a birthstone for meaning, appearance and durability — and know that what feels “traditional” is often a modern decision built on layers of history.