These bright yellow mimetite crystals are from the Congresso-Leon Mine, in the Leon Group, San Pedro Corralitos, Casas Grandes Municipality, Chihuahua, Mexico. This mine is famous for the mimetite specimens that were found there decades ago. It is arguable that they set the standards for mimetite specimens in the world of mimeral collectors. This is not the most impressive piece as far as size or aesthetics but it is a nice example of the botryoidal or cauliflower like formations of sparkling bright yellow crystals that the locale is famous for. It measures 1 5/8 x 1 3/16 x 5/8 inches or 41 x 31 x 16 mm.