Moonstone (bead form)

Hardness: 6-6.5 (Mohs scale); Color: Typically colorless with a white, blue, or sometimes peach or gray adularescence (schiller effect); Luster: Vitreous to pearly; Crystal Structure: Monoclinic; Cleavage: Good in two directions at nearly 90 degrees; Specific Gravity: 2.56-2.59

Moonstone forms in igneous (especially granitic pegmatites) and metamorphic rocks, often associated with other feldspar minerals. The adularescence is caused by the diffraction of light due to alternating layers of two different feldspar minerals (orthoclase and albite). Its geological age can vary widely depending on the host rock formation.

Predominantly used as a gemstone in jewelry, where its unique adularescence is highly prized. Also collected as mineral specimens. The bead in the image is a common way moonstone is used in jewelry, such as necklaces and bracelets.

Moonstone is the state gem of Florida (USA), commemorating the moon landings, which launched from Florida. Historically, moonstone has been associated with lunar deities and believed to bring good fortune, enhance intuition, and promote emotional balance. It has been a popular gemstone for centuries, particularly during the Art Nouveau period.

In the field, raw moonstone might appear as dull-looking feldspar. Identification usually relies on its characteristic adularescence, which can be observed by rotating the stone under light. Common locations include Sri Lanka (known for fine blue moonstone), India, Madagascar, Myanmar, Tanzania, and the USA (Virginia, Pennsylvania). Collectors often look for strong adularescence and desirable body color. In bead form, as shown, it's identified by its milky, iridescent sheen. Distinguishing it from similar-looking chalcedony or synthetic materials requires examination of its unique optical effect.