Book Description: Some minerals are extremely softâ€”as soft as baby powder. Other minerals are extremely hardâ€”like diamonds, the hardest natural substance in the world. Some rocks were once extremely hotâ€”they were made from magma deep under the earth.Do you know that you use minerals when you look in a mirror, brush your teeth, or sprinkle salt on your French fries? Find out all the answers about rocks and mineralsâ€”even how to study them yourselfâ€”when you dig in to Extreme Rocks & Minerals! Q&A.