There is a long standing tradition of associating gems with astrological signs. Belief in the magical and mystical power of gems goes back to ancient history. The ancient Babylonians used gems as talismans, associated them with astrology, and believed in their healing properties. This tradition continued through the ancient Greeks and Romans, whose writings on gems, mostly regarding their medical properties, have passed down to us. Similar beliefs were held by many other ancient peoples of the world.

These ancient traditions continued throug the Middle Ages. In Medieval Europe, a tradition developed of the 'lapidary', a book of gemlore describing the symbolism and associations of gems, the properties they were believed to have, and the supposed benefits of contemplating or wearing them. The blue of Sapphire, for example, was considered to raise the thoughts to heavenly things and so be suitable wear for clerics. Large numbers of these lapidaries were produced and sold.

In modern times, gems and crystals are still thought by some to have healing powers. Traditionally, particular gems were believed to hold these powers through their association with particular gods, saints, heavenly bodies, or astrological signs. These traditions are often carried through to modern times. Modern healers often have other explainations for their art, usually relating to the effects of light reflected off or channeled through the stones, or to some form of vibration within the crystals.

Although there is some variation in the stones linked with each sign, the most common associations are shown on this table. It gives a birthstone and the stone linked with the ruling planet. Other associations of stones are made by some astrologers, such as 'talismanic', 'mystical', or 'lucky charm' stones.