Prehnite is a hydrous calcium aluminum silicate mineral, generally discovered in earthy forms, crusts, or as distinctive crystals that range from bottle-green to yellow-green. It frequently develops in cavities within basalt or other volcanic formations, often in conjunction with various minerals like zeolites, calcite, and datolite. Prehnite is characterized by its vitreous to pearly sheen and has a hardness of 6 to 6.5 on the Mohs scale. This mineral is favored by collectors for its appealing hue and connections to other intriguing minerals. While it is not usually utilized as a gemstone due to its hardness and cleavage properties, it can be shaped and polished for decorative applications.