Laumontite (Ca(AlSi2O6)2·4H2O) is a zeolite containing loosely bound water. The water escapes easily so specimens can easily become dehydrated and crumbly.
Compared to many zeolites, the structure of laumontite is fairly simple. The structure consists of layers like the one above, seen in the a-b plane. Purple tetrahedra are silicon, yellow are aluminum.
The layers are joined face to face in pairs. Green represents calcium atoms, blue represents water. Lighter atoms and polyhedra are in the background.
Side view of the structure, looking down the b-axis. The a axis is vertical and the c-axis slants from lower left to upper right, parallel to the rows of water molecules. On the left is the tetrahedral structure with calcium and water. In the center is simply the tetrahedral structure. On the right are the layers individually colored.
Created 22 April 2013, Last Update 16 Jun 2013
Not an official UW Green Bay site