Birthstones by month, color and meaning.

Birthstones are gemstones conventionally associated with a calendar month, a zodiac sign or a date of birth. There is no single universal list. At least thirteen documented traditions assign different stones to the same month, and the list most widely used today was standardized in 1912 by American jewelers and amended in 2002, 2016 and 2022.

By trade convention rather than by any scientific rule. The modern list was agreed in 1912 by the American National Association of Jewelers, which fixed one stone per month from several competing older lists. Stones have been added since, usually when a newly available gem gained commercial importance — tanzanite in 2002 and spinel in 2016 are the clearest examples.

The usual account traces them to the breastplate of Aaron described in Exodus, which carried twelve stones. The first-century historian Josephus and later St Jerome connected those twelve stones to the twelve months. Whether the original stones can be identified with modern gem species is disputed, because ancient names described color rather than mineral composition. Josephus.

Three reasons: an older traditional stone was kept alongside a newer one, a stone became too expensive or too scarce for mass jewellery and an affordable alternative was added, or a newly discovered gem was introduced commercially. June, August and December each carry three stones in the modern list; March, October and November carry two.

January is deep red garnet, February purple amethyst, March blue-green aquamarine, April colorless diamond, May green emerald, June white pearl, July red ruby, August yellow-green peridot, September blue sapphire, October iridescent opal, November golden topaz and December violet-blue tanzanite. Months with more than one stone have more than one color.

Alexandrite, June's color-change chrysoberyl, is the rarest of the modern birthstones in gem quality; fine material above one carat is scarcer than diamond of equivalent size. Painite and red beryl are rarer still but belong to no birthstone list. Tanzanite comes from a single deposit in Tanzania, which makes it geographically the most restricted.

Per carat at gem quality, ruby leads: untreated Burmese material with strong color regularly exceeds other birthstones at auction, with fine emerald, alexandrite and blue sapphire following. Within one species prices vary by more than a hundredfold depending on color, clarity, origin and treatment, so a species-level ranking is only a starting point. See current price bands.

Diamond, at 10 on the Mohs scale, followed by ruby and sapphire at 9. These three suit daily wear in rings. Pearl at 2.5 to 4.5 and opal at 5 to 6.5 are the softest and should be set in pendants or earrings rather than rings, or reserved for occasional wear. Browse gemstones by hardness.

Traditional birthstones are the stones in use before the 1912 standardization, which varied by country and period. Modern birthstones are the standardized list agreed in 1912 and amended since. They differ for eight of the twelve months — August is peridot in the modern list but sardonyx in the traditional one, and December is tanzanite rather than turquoise. Compare all thirteen traditions.

There is no scientific evidence that gemstones affect physical health. Healing associations are documented beliefs belonging to specific traditions, and this site records them as beliefs with their cultural origin attached, never as medical claims.

Check refractive index, specific gravity and inclusions — the three properties that separate a species from its simulants. Natural stones usually contain inclusions that laboratory-grown and glass equivalents do not. For anything of value, ask for a report from an independent laboratory such as GIA, AGS, SSEF, Gübelin or GRS. A seller's own certificate is not an independent report. How to read a laboratory report.

A laboratory-created gemstone has the same chemical composition, crystal structure and optical properties as its natural counterpart; it is a real gemstone, grown in weeks rather than millions of years. A simulant only looks similar — cubic zirconia imitating diamond, for instance — and has different properties entirely. Laboratory-created stones typically cost a small fraction of natural equivalents and must be disclosed as such at the point of sale.