Analcime - Encyclopedia

    Class : Silicates
    Subclass : Tectosilicates
    Crystal System : Triclinic
    Chemistry : NaAlSi₂O₆ . H₂O
    Rarity : Quite common

Analcime is a mineral whose composition, structure and origins are similar to zeolites and feldspathoids, a group in which it is sometimes classified. It is a low temperature hydrothermal mineral that occupies the cavities of volcanic rocks (basalts, trachy-basalts and more rarely phonolites). It is associated with zeolites and prehnite, but it can also be found in nepheline syenites and their pegmatites. It forms a series with pollucite. The analcime owes its name to the Greek analkis (weak) to emphasize the low electrostatic charge that this mineral develops when heated or rubbed. The crystals can be large (sometimes decimetric), usually trapezoidal, exceptionally cubic. They are colorless, more often milky white, sometimes pink, occasionally yellowish or greenish. It is a mineral that presents no particular use, crystallized specimens are sought after collectors.

The analcime frequently shows polysynthetic twins on {001} and {110} visible only in thin section under polarized analyzed light.

No fake inventories for this species.