analtsiitti

Analtsiitti is a zeolite mineral with the chemical formula (Na,K)AlSi2O6·H2O. It is a tectosilicate belonging to the feldspathoid group and crystallizes in the isometric system, typically forming prismatic or trapezohedral crystals. Analtsiitti is characterized by its white to colorless appearance, vitreous luster, and hardness of 5 to 5.5 on the Mohs scale. It is relatively light, with a specific gravity of around 2.25.

The mineral is found in a variety of igneous rocks, particularly in sodic or alkaline magmas such as phonolites, trachytes, and basalts. It often occurs as secondary infill in vesicles and cavities within these rocks. Analtsiitti can also be found in some metamorphic environments. Notable occurrences include those in the Auvergne region of France, the Faroe Islands, and the Deccan Traps of India.

Analtsiitti is not of significant economic importance, though it has been investigated for its potential use as an ion exchanger and adsorbent due to its porous structure. Its primary significance lies in its geological occurrence, providing clues about the formation conditions of certain igneous rocks. The name "analtsiitti" is derived from the Greek word "analtein," meaning "to counteract," referring to its inability to become electrically charged when rubbed, unlike some other minerals. It is a relatively common mineral in specific geological settings.