Quartz (amethyst) + Sphalerite Naica, Saucillo, Chihuahua, ...
Description: Quartz (amethyst) + Sphalerite Naica, Saucillo, Chihuahua, Mexico 7,3 x 5,4 x 3,9 cm. Prismatic crystals partially coated by Calcite and on Sphalerite matrix. Amethyst is not especially common at Naica.