.5" Purple, Twinned Aragonite Crystal - Valencia, Spain

The mineral aragonite is named after Molina de Aragon, Spain, the mineral's type locality. There are multiple sites in Spain that produce aragonite crystal specimens, some of which exhibit brilliant purple coloration. Impurities within aragonite specimens that could alter the color of the crystals include strontium, magnesium, lead, and zinc.

Aragonite is one of two common calcium carbonate (CaCO3) minerals: the other is calcite. Aragonite is a pseudomorph after calcite: its crystal lattice differs from calcite, resulting in a different crystal shape. It displays a translucent to white color when pure, and when impure can vary between yellow, green, pink, blue and brown. It typically forms in low-temperature hydrothermal veins, in hot springs, and as precipitates from chemicals in sedimentary rock. It can also form under biological processes: aragonite forms naturally in most mollusk shells, and as the calcareous endoskeleton most corals.