具体描述
Some minerals are extremely soft--as soft as baby powder. Other minerals are extremely hard--like diamonds, the hardest natural substance in the world. Some rocks were once extremely hot--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 minerals--even how to study them yourself--when you dig in to "Extreme Rocks and Minerals QandA."
