|Asia||Nasik District, Maharashtra State, India||4 ½" x 1 ½" x 1"|
Scolecite belongs to a group of minerals called zeolites. The word zeolite comes from Greek, meaning "boiling stone." All zeolites contain loosely bound water molecules that can be driven off with mild heating. The crystal structures of zeolites contain large (on an atomic scale) channels and voids. The channels are of different sizes, and they can selectively trap atoms or molecules of appropriate dimensions and allow smaller ones to pass. Natural zeolites, and many synthetic compounds with similar crystal structures, are therefore sometimes called "molecular sieves." In the crystal structure of scolecite, shown to the right, it is easy to see the channels viewed down their length. The chemical formula of scolecite is CaAl2Si3O10 - 3H20. In the model below, Ca is large blue, Al small light blue, Si small dark blue, and O is red. Water molecules have been omitted.
Natural and synthetic zeolites have many industrial uses: water softeners and purifiers, catalysts, agricultural water moderators, air purifiers, and a growing list of dozens of other industrial and scientific applications. You may even have some at home - in your laundry detergent, potting soil, or cat litter.