Heulandite

Named after the English mineral collector, John Henry Heuland (1778-1856), this mineral is a member of the zeolite group of minerals. It is characterized by its crystal form and one direction of perfect cleavage with pearly luster. It is usually found in cavities in basalt and as a devitrification product from volcanic glasses.

Mineral Photos courtesy of R.Weller/Cochise College