Birthstone

A birthstone is a gemstone that represents a person's month of birth. Birthstones are often worn as jewelry and as pendants.

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 Exodus regarding the breastplate have varied widely, however, 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 because, as the book of Revelation states "their name would be inscribed on the Foundation Stones, and his virtue". Practice became to keep twelve stones and wear one a month. Wearing a single birthstone is only a few centuries old, although modern authorities differ on dates Kunz places the custom in eighteenth century Poland, while the Gemological Institute of America starts it in Germany in the 1560s.

Modern lists of birthstones have little to do with either the breastplate or the Foundation Stones of Christianity. Tastes, customs and confusing translations have distanced them from their historical origins, with one author calling the 1912 Kansas list (see below) "nothing but a piece of unfounded salesmanship."

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

...
Wikipedia