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Cave formations are called speleothem, from the Greek word spelaion, cave and thema meaning deposit. Almost all of them are made of calcite, the crystal of calcium carbonate. Different minerals and different movements in the water account for an incredible variety of cave formations.
The artistry of water and time created the entrance to this limestone cave in Patagonia, Chile. Limestone is a soluble rock, and over hundreds of thousands of years, the slow movement of water can work like a chisel. Geologists call these structures solutional caves. Get Wallpaper.