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Carlsbad Caverns Minerals

Mineral deposits in Lechuguilla Cave take on fantastical forms in Carlsbad Caverns National Park, New Mexico. Stalactites of calcite and a small aragonite formation appear as if in a magical backdrop. Calcite and aragonite are the two crystal forms of calcium carbonate, a property of minerals geologists call dimorphism. Their crystal structure sets them apart: calcite forms hexagons and aragonite forms rhombohedrons.

Photograph by Michael Nichols