Erionite is a naturally occurring fibrous mineral that belongs to the zeolite group. Some of the synonyms for erionite are clinoptilolite, chabazite, and mordenite. Erionite is commonly found in volcanic tuff, but it also occurs as a secondary mineral in hydrothermal veins and sedimentary rocks. Clinoptilolite is a type of zeolite that is widely used in various applications, including water treatment and soil conditioning. Chabazite is also a type of zeolite that is commonly found in volcanic rocks and sedimentary rocks. Mordenite is a type of zeolite that can be found in volcanic rocks and alkaline rocks. Despite their different names, these minerals share similar chemical and physical properties and are often used interchangeably in scientific literature.