Moonstone is a feldspar mineral, a potassium aluminum silicate, Its crystal system is monoclinic and prismatic. Moonstone was named after its blue-white sheen, which is caused by its lamellar structure.
It is found in Sri Lanka, Madagascar, Burma, Australia, India, and the United States.
Moonstone was used in Roman jewellery almost two thousand years ago, and even longer ago in the Orient.
It was a popular choice of jewellers during the Art Nouveau period. In India, Moonstone has always been a sacred stone, with special significance for lovers. It was believed that placing Moonstone in their mouths when the moon was full would allow them to see the future. Moonstone is also a traditional wedding gift there, for bringing harmony to the marriage.
In Europe, Moonstone was said to reconcile estranged lovers, and to cure sleeplessness.

Moonstone can come in a number varieties, such as White Moonstone, Rainbow Moonstone, Green Moonstone and Black Moonstone. Each with they own properties but all Moonstones are said to have a feminine energy, and considered to help bring a balance to the male-feminine energies.
Moonstone is said to calm overreaction to situations, soothes emotional instability and stress, and stabilises the emotions.