Zeolite

ZEOLITES form a large group of minerals characterized by an unusual crystalline structure. ZEOLITES are absorbent due to an open, three-dimensional crystal structure. When they are heated, the water they contain is expelled continuously and not in certain amounts. It's as if the water was gushing instead of dripping. Once the water is removed, the mineral becomes very receptive to incorporating new molecules into the spaces created in its structure. They are used in sorption pumps for vacuum systems. ZEOLITES are glassy secondary minerals that form in lava cavities and plutonic rocks.