Which cave in Arizona is known for its exceptional variety of speleothems and is a state park?

The Arizona cave known for its exceptional variety of speleothems and protected as a state park is Kartchner Caverns. The limestone caverns are part of Kartchner Caverns State Park in Cochise County, southeast of Tucson.

Cavers Gary Tenen and Randy Tufts discovered the passage system in 1974 after following warm, moist air from a narrow crack in a sinkhole. They kept the discovery secret for 14 years to protect its pristine formations from vandalism. The site eventually became a state park, and the caverns opened to the public in 1999 after extensive conservation engineering.

Kartchner Caverns contains formations that have been growing for 50,000 years or more, including stalactites, stalagmites, columns and brushite moonmilk. The Throne Room features the large column Kubla Khan, while the Big Room is famous for its extensive formations.

Cave of the Bells, Peppersauce Cave and Colossal Cave are also Arizona caves, but they are not the state park identified by this combination of clues.