Chip and brush away using safe wooden brushes (8 per block provided). at these awesome, easy to use excavation blocks and uncover fossils such as REAL dinosaur bone, ammonites, sea squid (orthoceras), fossil clams, crinoid stems, sea urchins and shark teeth (even some Megalodon shark teeth, from the largest shark that every lived! Plus awesome minerals such as REAL rough rubies, emeralds, amethyst crystals, citrine, quartz, glittery pyrite (fool's gold), variety of colorful Brazilian polished agates and more. ..When using these for group events at schools, camps and parties, we use one block per 6 kids our DINOSAURS ROCK parties and school programs. Many customers set up stations and rotate kids through along with other activities such as Geode opening, shark tooth necklace-making and making art from Dinosaur & Fossil Rubbing plates (other products all found in our Superstore). Comes with tools and complete instructions. Note: No fancy packaging, just tons of real specimens (compare to packaged kits with just a few pieces in them!) to collect and enjoy. Each block is made from safe, sanitized playsand and plaster and of course fossils and minerals galore. The ultimate dinosaur gift or dinosaur party activity or dinosaur classroom resource! Hefty 12" x 4 1/2" x 3"