Crayola® Modeling Clay. Crayola Modeling Clay enables children to create in three dimensions. Oil-based clay is non-hardening, repels water and can be used multiple times - for hours at a time. Modeling clay builds fun into learning as it is formed and shaped by children's imaginations. Package includes four individually wrapped colors: red, blue, yellow and green. (1/4 lb. per color, 1 lb. per set)