This bytownite is from the Dorado Mine in Casas Grandes Municipality, Chihuahua, Mexico. This mine is operated exclusively for the recovery of bytonite. It is a gemstone variety of the feldspar mineral anorthite and it contains the elements Ca, Na, Al, Si and O. This is a typical crystal with crude crystal faces and blunt terminations. It is translucent with a frosty clay stained exterior. It measures 16 x 15 x 8 mm. It weighs 14.5 carats.