Western custom

The first century Jewish historian Josephus believed there was a connection between the twelve stones in Aaron's breastplate (as described in the Book of Exodus), the twelve months of the year, and the twelve signs of the zodiac. Translations and interpretations of the passage in Book of Exodus regarding the breastplate have varied widely, with Josephus himself giving two different lists for the twelve stones. George Kunz argues that Josephus saw the breastplate of the Second Temple, not the one described in Exodus. St. Jerome, referencing Josephus, said the Foundation Stones of the New Jerusalem (Revelation 21:19–20) would be appropriate for Christians to use.

In the eighth and ninth century, religious treatises associating a particular stone with an apostle were written, so that "their name would be inscribed on the Foundation Stones, and his virtue. The custom of wearing a single birthstone is only a few centuries old, though modern authorities differ on dates. Kunz places the custom in eighteenth century Poland, while the starts it in Germany in the 1560s.

Traditional birthstones

Ancient traditional birthstones are society-based birthstones. The table above contains many stones, which are popular choices, often reflecting Polish tradition.

The Gregorian calendar has poems matching each month with its birthstone. These are traditional stones of English-speaking societies.

Modern birthstones

In 1912, in an effort to standardize birthstones, the (American) National Association of Jewelers (now called Jewelers of America) met in Kansas and officially adopted a list. The Jewelry Industry Council of America updated the list in 1952, by adding Alexandrite for June, citrine for November and ''pink'' tourmaline for October. They also replaced December's lapis with zircon and switched the primary/alternative gems for March. The American Gem Trade Association added tanzanite as a December birthstone in 2002. In 2016, the American Gem Trade Association and Jewelers of America added spinel as an additional birthstone for August, Britain's National Association of Goldsmiths created their own standardized list of birthstones in 1937.

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