Pumice
Source: World Wide
Chemical: Lava
Crystal System: None
Formation: Highly porous rock from cooling lava flows
Properties: It floats in water. A floating rock! As seen
in the photograph at left. One on a table top, and second floating
in water. And it is used for many purposes...from a rather famous
hand cleaner to landscaping. Which is where I found this specimen
shown at left....in a flower bed around a streetlight in Naples,
Florida. Thanks, guys!