7" Crystal Filled, Celestine (Celestite) "Egg" - Madagascar
This famous Madagascar locality discovered in 1967 has an annual production of about 15 tons of the material. It is located near the village of Sakoany, on the western side of the banks of the Betsiboka River. The celestine-bearing layer is found in a maximum 30 m thick lens between layers of crinoidal limestones and sandy greywacke from the end of the Cretaceous. It is mined by digging shafts up to 15m (50 feet) deep in order to reach the deposits. The celestine occurs mainly as 2 different types: as geodes up to a maximum size of 60 cm in diameter, and as crystal clusters up to 15 cm in diameter.
The world's largest known geode, a s geode 35 feet (10.7 m) in diameter at its widest point, is located near the village of Put-in-Bay, Ohio. The geode has been converted into a viewing cave, Crystal Cave.