Class : Silicates
    Subclass : Tectosilicates
    Crystal system : Monoclinic
    Chemistry : LiAlSi₄O₁₀
    Rarity : Uncommon

Petalite is a rare lithium silicate, typical of sodolithic pegmatites. It rubs shoulders with pollucite (hence the old name "castor" given to petalite and "pollux" for pollucite). it is also associated with other lithium minerals such as elbaite, lepidolite or spodumene. Its name is taken from the Greek petalon (leaf) to illustrate its perfect cleavage. The petalite has a perfect pearly cleavage according to {001} and a grayish white color, rarely greenish or pinkish. It generally occurs in cleavable foliated masses, difficult to distinguish from feldspar, rarely in crystals, elongated according to [100] and flattened on {010}, ordinarily embedded in quartz. It is locally an important lithium ore and is occasionally cut as a gemstone when transparent.

Main photo : Petalite from Catri, Island of Elba, Italy © Matteo Chinelatto

The twins are common and lamellar on {001}.

No fakes listed for this mineral species.