Clay is decomposed igneous rock that picks up impurities as it travels, giving it plasticity or the ability to be shaped while still holding its form. When working with clay, proper safety precautions must be taken such as wearing protective clothing and a dust mask. Clay must be kneaded to remove air bubbles and create consistency, and kept moist but not wet. It is important to keep clay wrapped in plastic when not working with it to prevent drying out.