While the Milpillas Mine is best known for its spectacular azurite specimens, it has also produced particularly good examples of a number of other species-- native copper, brochantite, volborthite, and cuprite to name a few. The latest surprise from this mine has been shattuckite. The last decade has seen a couple good finds of this species, most notably in Namibia and Congo, and now those are joined by these Mexican examples.
This is a particularly large piece-- the main face (pictured at right) is covered in shattuckite balls with interspersed tufts of lighter aurichalcite. This is not a perfect piece-- a number of the balls are sheared-- but this is still an exceptional rich example of the species for the price (think about how much the Namibian ones go for) and the aurichalcite in the matrix makes for a particularly striking appearance.