(Bed) Rocks and (Flint) Stones

Question: What melts to form volcanic lava?

Answer: Lava is hot, liquefied rock that flows from a volcano or other opening in the surface of Earth. Igneous rock is formed when lava cools and hardens.

Question: How much does a carat weigh, in milligrams?

Answer: A carat is a unit of weight used exclusively to measure precious stones. It is equal to 0.007 ounce (200 milligrams).

Question: To which of these materials is a diamond most closely related?

Answer: Diamonds are made of pure carbon that has been subjected to tremendous pressure and heat and formed deep underground.

Question: Which of these is a kind of stone?

Answer: Meerschaum, which is German for "sea foam," is a light, chalky stone. It is often used to make pipes.

Question: What is the name for a dark volcanic rock?

Answer: Basalt is a dark volcanic rock. It is often found in mountains.

Question: Which of these is not a type of rock?

Answer: Sedimentary rocks form in layers. Igneous rocks are produced by heat. When those rocks change, they are called metamorphic.