The pearl is the oldest known gem, and for centuries it was considered the most valuable. Pearls were a symbol of the moon and had magical powers which was thought to bring prosperity and long life to those around them. Pearls have been considered divine gifts and suited for royalty. Pearls have also been considered ideal wedding gifts due to their symbolism of purity and innocence. Pearls have been prescribed as a love potion. Some cultures have used pearls to cure a variety of ailments such as indigestion, fever, and heart disease. Today, the main component of pearls is calcium carbonate and is used as an antacid as well as vitamin. At the age of 94, Mikimoto, the founder of the cultured pearl industry stated, "I owe my fine health and long life to the two pearls I have swallowed every morning of my life since I was twenty."