Chihuahua, Mexico

Without Aragonite, many of Earth’s organisms could not exist. Most invertebrates use Aragonite to grow their exoskeletons and shells by secreting the mineral from waters that would ordinarily yield only Calcite.

This sky-blue and stormy-grey Aragonite specimen is a standout piece that sparkles and glitters under the light, thanks to the mixture of microcrystals and small prismatic completely covering the bubbly aggregate’s surface.