This is a Chinese Viewing Stone, also known as a Suiseki Stone from the Rare Stone Museum in Thailand. It stands about 22' tall and has lots of intricate caves and passages. It also has fossils of crinoids in the bottom and the stone is known commonly as, "Chinese Limestone" being black in color. I am a geologist and have collected and sold these for years along with Bonsai trees. Pictures is the stone with a golf ball to show the size. It stands on a custom carved wood base for display.