Class : Silicate
    Subclass : Inosilicate
    Crystal system : Triclinic
    Chemistry : Ca₅Si₉O₂₃. 9H₂O
    Rarity : Uncommon

Okenite is a spectacular calcium silicate, mainly present in geodes and basalt cavities, in which it accompanies zeolites (apophyllite, gyrolite, laumonite, etc.), prehnite and calcite. It was named in honor of the German naturalist Lorenz Ocken. Its morphology is characterized by extremely fine needle-like crystals which group together to form spiky balls ("sea urchins" or "cotton balls") or radiate tufts. Transparent to translucent, with a vitreous luster, okenite is colorless to white, sometimes slightly yellow. It is a mineral that has no particular use, it is only intended for mineral collectors.

This mineral is not present in the French underground.

Existing but invisible to the naked eye.

Okenite is always naturally white or slightly yellow in color. It is frequently dyed in various colors (most often canary yellow or green, but also sometimes red or blue and potentially any color) in order to facilitate its sale. These treatments having been widely denounced, they have become rare today on the market.