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 xls, would be fine for ANY locality, though.