Natroliitti

Natroliitti is a relatively rare mineral belonging to the zeolite group. Its chemical formula is Na2Al2Si3O10·2H2O. Natroliitti crystallizes in the orthorhombic crystal system, often forming prismatic, needle-like, or radiating aggregates. These needle-like crystals are a distinctive characteristic. The color of natroliitti can vary, commonly appearing white, colorless, gray, or sometimes yellowish or reddish due to impurities.

The hardness of natroliitti is typically between 5 and 5.5 on the Mohs scale, making it moderately hard. It has a relatively low specific gravity. Natroliitti is found in various geological environments, often associated with volcanic rocks, particularly in the cavities and vesicles of basalt and other extrusive igneous rocks. It can also occur in hydrothermal veins and altered sedimentary rocks.

Notable occurrences of natroliitti include locations in the Czech Republic, Norway, Ireland, and the United States. While not a significant ore mineral, natroliitti is of interest to mineral collectors due to its aesthetic crystalline forms and its role in understanding geological processes. Its porous structure, characteristic of zeolites, allows it to absorb and release water, which can influence its stability and appearance.