An unusual specimen! Most Milpillas malachite is secondary - that is, it formed as a replacement of former azurite crystals. This piece, however, is composed of unusually shaped, curved malachites as the matrix. Later, a second generation of malachite formed atop, after replacing azurite crystals, thus showng that there were at least 3 times of different crystallization on this one piece of what is now all malachite. Unusual! Joe Budd photos.