These pagan beliefs became incorporated into later religions including judaism and christianity. Astrology is also a link with these earlier beliefs. With the passing of time and fashions, different gemstones have been ascribed to different months. It is thought that, originally, colour was the major attribute which determined a person's birthstone. During the eighteenth century, the connection between birthstones and particular months received a wave of popularity, and many different lists came into being.
Gemstones associated with the zodiac signs sometimes coincide with the birthstones by month.