This is a fine example of a double pseudomorph where the originally formed azurite crystals were later changed to malachite which, in turn, became chrysocolla. The crystals, to 1.4 cm across, exhibit translucence along with the most beautiful, deep robin's-egg blue color. Truly, they are a unique thing caused by a very unusual combination of events at this mine. This is an old USA classic, but seldom seen today on the market. I buy every one I see!