Several polished crystals are buried in a block of plaster of paris. A hammer and pokey double ended tool and a stiff brush are included to chip away the plaster to reveal the jewels inside. Put a bit of newspaper down underneath as doing it is dusty, but all part of the fun for our 6yr old boy. We all wanted a go, me, 9 yr old daughter and husband all couldn't resist it! In real terms it doesn't take all that long to chisel them out, but it kept my son quiet for hours at a time, he was really engrossed! Try the glow in the dark dinosaur, dino dig I think it's called as that's really good too.