The traditional concept of precious stones according to the birth dates (birthstones) is based on the Bible. They firstly appeared on the Breastplate of Aaron, also known as “Aaron the Priest”. Aaron was the brother of Moses, a prophet and first High Priest of the Israelites.
The precious stones on his breastplate were arranged in four rows of three, symbolizing the 12 tribes of Israel.
Breastplate on the front of the central Sephardic synagogue in Ramat Gan (source: https://commons.wikimedia.org)
To this tradition, Christians have established their symbolism of precious stones
called the cornerstones of New Jerusalem. The stones were now associated with twelve apostles. Each of them stood above one month of the year and was symbolized by one zodiac sign.
Today’s fashion to wear a stone by date of birth dates back to the Renaissance, which was devoted to the study of astrology and alchemy. The history has preserved several historical lists of precious stones by date of birth. In modern times, gems in these lists have often been replaced by stones cheaper and more widely available, whether on the basis of color similarities or other guides. Today we usually encounter a combination of different traditional lists with a star, planetary, talisman or ayurvedic stones.
(article source: http://www.drahe-kameny-mineraly.cz/)