Laumontite is a zeolite mineral, Hydrated Calcium Aluminum Silicate. This specimen is from a small batch of rare California laumontites that came out of the Don Belsher collection about 6 years ago. It has creamy-yellow color and actually a bit of luster to it. The crystal is terminated on one end. Usually this stuff disintegrates over time but these seem remarkably stable, and I am sure the piece has been lightly coated with a shellac to ensure it stays that way.