During the last part of the 19th century miners at the booming mining camp at Bisbee in the Arizona Territory began finding natural caves. These caverns were more than the typical calcite and aragonite filled openings stained by iron and manganese oxides. These caverns contained substantial amounts of malachite, azurite, rosasite and even cuprite. As a result the caverns were at times the formations were colored in deep greens and blues. It was learned that these caves formed as the result of the sugergene (oxidation) alteration of sulfides. The book begins with the history of local cave discoveries and then becomes more technical as it examines the speleology and mineralogy.