This is an absolutely gorgeous jewelry box made out of slabs of polished Rhodochrosite from the famous Capillitas Mine in Argentina. It measures 8" wide and the interior is lined in black felt.
Rhodochrosite is a manganese carbonate mineral with them chemical composition MnCO3. The crystals typically have a pink-red coloration and cleaves with rhombohedral cleaving in three directions. It forms from hydrothermal pockets and can be found as both crystals and in banded formations.