1. Some rocks can actually float on water. Pumice is a lightweight volcanic rock formed when hot, bubbly lava cools super fast. It is packed with tiny trapped air pockets, making it so light that it floats like a piece of wood in a bathtub!

2. Every rock on Earth fits into one of three main families. Geologists group rocks into three types based on how they form: Igneous (made from cooled lava or magma), Sedimentary (made from squished layers of sand and mud), and Metamorphic (cooked and squeezed by intense heat and pressure deep underground).

3. Crumpled plant and animal fossils are hidden inside rocks. Almost all fossils of dinosaur bones, sea shells, and ancient ferns are found in sedimentary rocks! Over millions of years, layers of mud and sand covered dead plants and animals, turning their remains into stone.

4. The Moon and Mars are covered in volcanic basalt. The dark, smooth spots you see when looking up at the Moon (called maria) are actually massive plains of solid black lava rock called basalt—the exact same kind of rock that makes up Hawaii's volcanoes!

5. Rocks are recycled by the Earth continuously. Through a process called the Rock Cycle, wind and rain break down big mountain rocks into sand, rivers wash the sand into the ocean to form new sedimentary rock, and tectonic plates sink that rock deep underground to melt it back into fresh volcanic magma!

6. Diamonds and pencil lead are made from the exact same thing. Both sparkling diamonds and dark pencil lead (graphite) are made entirely of the element carbon! The difference is that diamonds were squished under immense pressure deep inside the Earth, locking their carbon atoms into an unbreakable crystal shape.

7. Earth's oldest rocks are over 4 billion years old. Scientists found ancient zircon crystals in Western Australia that are about 4.4 billion years old! That means those tiny mineral grains formed shortly after the Earth itself was born.