This geode is from Morocco. It is a formation that is called a septarian nodule because of the random polygonal patterns found within which are called septaria. The formation is a sedimentary nodule, concretion or geode type structure whose interior is filled with contrasting deposits of aragonite and calcite. This piece has been cut and polished to a gem-like luster. Each half measures approximately 2 x 1 11/16 x 1/2 inches or 50 x 44 x 12 mm.