Zodiac gems, also known as Zodiac Birthstones, are Gemstones that are based on your astrological sign, or Rashi. Each zodiac sign is associated with one or more Gemstones. Astral stones, often referred to as zodiac or Zodiac Birthstones or gems, are derived from astrology and have played a significant role in numerous religions since antiquity. Birthstones have been a tradition since prehistoric times, when people believed that particular stones may bring good fortune, good health, and wealth.