Penn Plax AG3 90 Bag Gemstones Decorative Aquarium Stones, Clear ADD A DECORATIVE TOUCH: great decorative accent for aquariums, terrariums, planters, and any other home dcor project. HELPS TO ANCHOR PLANTS: helps to keep plants and other light decorations from floating to the surface. (plants and other decorations not included) SAFE FOR USE: the eye catching collection of gemstones are safe for both your plants and aquatic life in your aquarium. (plants and other aquatic life not included) SMALL SIZE: unfit for use as a childrens toy, each gemstone measures approximately 2 cm in diameter.