"Rocks can grow taller and larger
When children grow, they get taller, heavier and stronger each year. Rocks also grow bigger, heavier and stronger, but it takes a rock thousands or even millions of years to change.
You can find rocks growing taller and bigger in caves and hot springs. In caves, rocks grow because water flowing along walls or dripping from the ceiling leaves behind minerals along the cave wall or floor, said Cory BlackEagle, a geologist at the University of Kentucky in Lexington and chair of the Geological Society of America's Karst Division. Cave rocks are usually composed of minerals such as calcite, aragonite, opal, chalcedony and others. Rocks formed by this dripping water are called stalactites when they grow down from the ceiling and stalagmites when they grow up from the floor. [In Photos: Stunning Stalagmite Structures Discovered in French Cave]"
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