We generally think of birthstones as a specific stone you wear based on the month you were born; however, they didn’t start out quite that way. The start of birthstones goes back to ancient times, but the actual list of current birthstones did not exist until 1912. This article on the history of birthstone jewelry explains:
The history of how birthstones came to be dates back to Biblical times. The book of Exodus in the Bible describes the Breastplate of Aaron, a religious garment, which contained 12 stones representing the 12 tribes of Israel. The jump was then made by ancient scholar Josephus that the 12 stones correlated to the 12 signs of the zodiac.
It was believed that each stone had powers of luck, healing, and prosperity if you wore it during its assigned month. In order to take full advantage of this idea, a person would have to possess all twelve gemstones and switch them out at the start of each month.
To read more on what birthstone is yours and the meaning behind it, check out the American Gem Society’s web pages on birthstones by month.