Zeolites- October 2018 Mineral of the Month
Taos Rockers mineral of the month is a family of minerals collectively known as Zeolites.
Zeolite is a group name for a large number of microporous framework alumosilicates which are built of corner-linked tetrahedra and contain exchangeable cations. This porous structure allows a wide variety of loosely held positive cations (Na+, K+, Ca2+, Mg2+) to be readily exchanged for others in a contact solution - hence one of the many uses of zeolites is in ion-exchange applicaitons (micro-sieving).
The term zeolite is attributed to Swedish mineralogist Axel Cronsetedt, who in 1756 observed that rapidly heated material (believed to be stilbite) produced large amounts of steam from water that had been adsorbed by the material [from the Greek - zeo, to boil, and lthos, stone]. Over 232 unique zeolite frameworks have been identified with over 45 occuring naturally. Zeolites are produced industrially on a large scale for such applications as commercial adsorbents and catalysts, water purificatiion, separation of gases and molecules, on-board oxygen generating systems, solar thermal collectors, and non-clumping cat litter.
The largest single use is the global laundry detergent market. Natural zeolites form where volcanic rocks and ash layers react with alkaline groundwater or in shallow marine basins (over periods of thousands to millions of years).
Thomsonite has been collected as a gemstone from a series of basalt lava flows along Lake Superior in Minnesota.
Some of the natural Zeolites available at Taos Rockers include:
Analcime Na(AlSi2O6) · H2O
Chabazite CaAl2Si4O12 · 6H2O
Heulandite CaAl2Si7O18 · 6H2O
Laumontite CaAl2Si4O12 · 4H2O
Mordenite (Na2,Ca,K2)Al2Si10O24 · 7H2O
Natrolite Na2Al2Si3O10 · 2H2O
Mesolite Na2Ca2Si9Al6O30 · 8H2O
Scolecite CaAl2Si3O10 · 3H2O
Pollucite (Cs,Na)2(Al2Si4O12) · 2H2O
Stellerite Ca4(Si28Al8)O72 · 28H2O
Stilbite CaAl2Si7O18 · 7H2O
Thomsonite (Ca,Na)6Al8(Al,Si)2Si10O40· 12H2O
along with other minerals often found associated with zeolites:
Apophyllite NaCa4(Si8O20)F · 8H2O
Cavansite Ca(VO)Si4010· 4H2O