I heard about those. The crystals are actually quartz. I heard that someone intended to steal one, it fell over and crushed the would-be thief. Each one has to be hundreds if not thousands of pounds.
Thanks for the link!
I appologize Roger but the crystals are actually a type of gypsum crystal called Selenite. This is also what makes them so fragile. Most of the columns weigh in excess of 10 to 20 tonnes. The theif actually was "cooked" to death as he took bags of fresh air with him into the mine where the air is thin, the humidity is 100%, and the temperature is 150 degrees farenheit/65 degrees celsius