Zeolite Group

Zeolites are a large group of mostly hydrous alumosilicate minerals and, rarely, beryllosilicates, zincosilicates and beryllophosphates, with a microporous molecular structure, known as the Zeolite Group. The Zeolite Group of minerals encompasses over 100 minerals including these gem-type minerals: Analcime, Barrerite, Chabazite, Epistilbite, Gmelinite, Goosecreekite, Heulandite, Laumontite, Leucite, Mordenite, Natrolite, Pollucite, Scolecite, Stellerite, Stilbite, Thomsonite and Yugawaralite. Many of these minerals are typically found only as very fine, radiating needles, cottony aggregates or radiating masses so gem quality crystals are somewhat rare. Some of them, such as Mordenite, Stilbite and Thomsonite are never found as gemmy, transparent crystals and are typically only available as cabochons.

The name Zeolite was introduced in 1758 by Swedish chemist and mineralogist Axel Fredrik Cronstedt (1722-1765) from the Greek words ζέω (zeó) meaning to boil, and λίθος (lithos) meaning stone. Cronstedt observed that a sample of Stilbite emitted steam when heated. Most Zeolites are hydrous minerals, meaning they contain water, therefore may emit steam when heated. Cronstedt discovered Nickel and Scheelite in 1751. The mineral Cronstedtite was named in his honor in 1821 by Professor J. Steinmann. Cronstedt's mineralogical books revolutionized mineralogy at the time and he is sometimes regarded as the father of modern mineralogy.