Custom Geode Bookend Silicone MoldsThese custom Geode Bookend molds come in two shapes giving you a choice in how you use them! Create two identical bookends, one at a time, or two different but complementary shapes for an organic look. The bookends from these molds measure 4. 5" x 3 and 5" x 2. 75 and each mold takes approximately 400ml of resin. Note: Because these are hand made molds cast from real geodes, there could be small lines or marks in the molds reflecting actual stone.