Blue Ribbon Ee-1136 Skull Geode Stone Exotic Environments Aquarium Ornament, Purple, 6.5 Inch (Ee-1130)

Geodes form in gas bubbles inside fresh lava or in rounded cavities in sedimentary formations. After rock around the cavity hardens dissolved silicates and/or carbonates are deposited on the inside surface allowing crystals like purple Amethyst to form inside the hollow chamber. Safe & non-toxic.