Al Ordway collected this specimen in 1967 according to his card, and it is the ONLY such piece I personally have seen go by. In fact, I was not even familiar with aurichalcite from the locale, though cyanotrichite has come to market on and off over the years. This small mine is a former Copper and Uranium mine worked from 1890-early 1900s. The Last Chance Mine in the Grand Canyon is located below the South rim, and is accessed via the Grandview Trail.; The mine itself is located on Horseshoe Mesa. Some collectors, such as Al, snuck back into the old workings over the years but I have never heard of any big finds, and the trek is surely dangerous. This piece, with brilliant blue, relatively robust aurichalcite crystals, would be fine for ANY locality, though.