Emeralds are known to us today as the birthstone for May. Anyone wearing emerald jewelry, as the birthstone poem says, "Shall be" "loved and happy." However, over the years, emeralds have been associated with more than just love and happiness. In the Middle Ages, emeralds were associated with not only love, but with the heavens. And emeralds were believed to contain strong healing powers. All in all, emeralds were considered as something of a super gem in the Middle Ages.
We know this from various writings. In 1349 Guillamuede Machaut wrote that "emeralds make every heart rejoice." He described a vision of the Holy City of Jerusalem with walls composed of various jewels including emeralds. In a late lapidarium (a genre of book in the Middle Ages specifically devoted to the examination of gems), Raymond Lull wrote of the emerald's healing powers. He wrote from his own experience claiming that simply holding an emerald helped ease a sick person's suffering. He wrote that emeralds helped keep away the devil, and prescribed it to King Robert of Sicily for manic fits associated with possession.
While we no longer see emerald as a super gem and associate it with the divine or healing powers, its association with love is what makes it May's birthstone. This gorgeous green gem, whether set in emerald rings or bracelets, emerald necklaces or earrings, is a thoughtful and stunning gift not only for someone born in May, but for any loved one.