Modern lists of birthstones have little to do with either the breastplate or the Foundation Stones of Christianity. Recreation of the high priest's breastplate in front of the central Sephardic synagogue in Ramat Gan, Israel Kunz places the custom in eighteenth-century Poland, while the Gemological Institute of America starts it in Germany in the 1560s. : 298 The custom of wearing a single birthstone is only a few centuries old, though modern authorities differ on dates. In the eighth and ninth centuries, 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.' : 299 Practice became to keep twelve stones and wear one a month.

Jerome, referencing Josephus, said the Foundation Stones of the New Jerusalem ( Revelation 21:19–20) would be appropriate for Christians. : 130–131 George Frederick Kunz argues that Josephus saw the breastplate of the Second Temple, not the one described in Exodus. : 275–306 Translations and interpretations of the passage in Exodus regarding the breastplate have varied widely, with Josephus himself giving two different lists for the twelve stones.

The first-century historian Josephus believed there was a connection between the twelve stones in Aaron's breastplate (signifying the tribes of Israel, as described in the Book of Exodus), the twelve months of the year, and the twelve signs of the zodiac. Birthstones are often worn as jewelry or as a pendant necklace. A birthstone is a gemstone that represents a person's period of birth, which is usually the month or zodiac sign.

Pink sapphire birthstone month