Shattuckite with Primary Malachite on Quartz

Shattuckite is a somewhat rare copper silicate hydroxide. It is formed when—atom by atom—its crystal structure replaces that of the previous mineral (in this case, malachite), with almost no change to the crystal's external shape.

Individual malachite crystals are rare, but when they do occur—as demonstrated by the unique specimen offered here—they appear as beautifully slender, needle-like prisms.