heulandiiitti

Heulandite is a mineral belonging to the zeolite group, characterized by its hydrated aluminosilicate structure. It commonly occurs as translucent crystals, often in shades of white, pink, or reddish-brown, though other colors are possible. The crystal habit is typically prismatic or tabular, often forming aggregates of radiating or parallel crystals. Heulandite is a relatively soft mineral, with a Mohs hardness of around 3.5 to 4, and exhibits perfect cleavage in one direction.

The name "heulandite" honors the English mineral collector John Henry Heuland. This mineral is typically found in cavities within volcanic rocks, such as basalt and andesite, where it forms as a secondary mineral through hydrothermal alteration. It can also be found in sedimentary rocks and in some metamorphic environments. Heulandite is known for its ability to absorb and release water, a common characteristic of zeolites, which influences its physical properties.

Economically, heulandite has limited direct applications due to its softness and the availability of other zeolites with more robust industrial uses. However, it is collected by mineral enthusiasts for its aesthetic appeal and crystal formations. In scientific research, heulandite serves as an example of zeolite structures and their formation processes within geological settings. Its presence can also provide clues about the hydrothermal history of the rocks in which it is found.