Lacquered Emerald Rose with Gold Trim May BirthstoneBirthstone Month: May Emerald Legend has it that emeralds could promote healing, cure diseases like malaria, and protect the wearer against evil spells. When placed under the tongue, an emerald supposedly provided the ability to predict the future. Cleopatra was well known for wearing a lot of emeralds since it was her favorite gemstone. Those born in the month of May tend to be loving and compassionate and can help people see past their differences