ˈprāˌnīt, ˈpreˌ- noun
( -s )
Etymology: German prehnit, from Col. Van Prehn 18th century Dutch officer who brought it from the Cape of Good Hope + German -it -ite (I)
: a pale green mineral Ca 2 Al 2 Si 3 O 10 (OH) 2 that occurs in crystalline aggregates having a botryoidal or mamillary structure but only rarely in distinct crystals and that is a basic calcium aluminum silicate (hardness 6-6.5, specific gravity 2.80-2.95)