Characteristics of Moonstone:

Chemical Name: Sodium potassium aluminum silicate

Formula: (Na,K)AlSi3O8

Colors: Colorless, white

Structure: Monoclinic

Hardness: 6-6.5

Specific Gravity: 2.6

Refractive Index: 1.50

Lustre: Vitreous

Streak: White

Locations: India, Sri Lanka, Tanzania, Kenya, New Zealand, Australia, Norway

What is Moonstone?

Moonstone, an opalescent variety of anorthoclase and other feldspars, has been used in jewelry for centuries. Ancient Romans believe it came from solidified rays of the moon, and linked it to their lunar deities. Typically made up of layers of sodium- and potassium-rich feldspars, Moonstone has a blue or white sheen – the result of the scattering or reflection of light by tiny intergrowth of minerals. The gem marketed as “rainbow Moonstone” is more properly classified as a colorless labradorite.

Moonstone is the US state gem for Florida, from where the Moon landings took off – but it does not naturally occur there.