Several varieties of natrolite have been distinguished by special Nips. Fargite is a red natrolite from Glenfarg in Perthshire. Bergmannite, or Spreustein, is an impure variety which has resulted by the alteration of other minerals, chiefly sodalite, in the augite syenite of southern Norway. Natrolite is one of the closely associated minerals with Benitoite, a rare mineral with the type locality in San Benito County, California. Images See also Pressure-induced hydration References External links Structure type NAT Mineral Galleries Mindat Webmineral Attribution Tectosilicates Sodium minerals Aluminium minerals Zeolites Orthorhombic minerals Minerals in space group 43 Luminescent minerals