Tufts, Tenen, and the Kartchners decided the best way to protect the cave was to develop it as a state park. Even the bill authorizing its purchase by the Arizona government in 1988 kept the cave's existence under wraps. One challenge in opening up the cave to tourists was to maintain the subtropical climate. At 68 degrees with 99 percent humidity, the cave has an evaporation rate 800 times lower than the desert air outside. Letting in too much air could halt the growth of existing speleothems, or cave decorations, and the birth of new ones.
Formations depend on moisture to grow.
That's why Kartchner has airlock doors. Soon after our group entered, a water droplet fell on my reporter's notebook. Cave Minerals of the World names Kartchner Caverns as one of the top 10 show caves for its rare minerals. The average length is 2 to 3 feet. Toward the end of the hour tour, visitors sit in a miniamphitheater.