Aragonite frostwork, taken in a cave in Nevada during field work. Mr. Rice writes, "Anthodites are speleothems (cave formations) composed of long needle-like crystals situated in clusters which radiate outward from a common base. Most anthodites are made of the mineral aragonite (a variety of calcium carbonate, CaCO3), although some are composed of gypsum (CaSO4ยท2H2O). The "needles" may be quill-like or feathery."
