Fifth Grade
Worksheets
Three Kinds of Rocks
Rocks can be put into three main groups, depending on how the rocks formed. Igneous rocks are rocks formed from fire. That is how they got their name. "Igneous" comes from the Latin word "ignis," which means fire.
Igneous rocks start out as melted rock called magma deep inside the Earth. When magma erupts onto Earth's surface, it is called lava. The rocks that form when lava cools are igneous rocks. Obsidian, basalt, and granite are igneous rocks. Granite is used as a building material. It is often used for the outside of buildings and for statues. It can be used for kitchen countertops.
Sedimentary rocks are another kind of rock. They are made of sediments - tiny bits of minerals, rocks, and seashells. Rocks on Earth's surface are constantly being weathered. They break down into these smaller sediments. Over time, layers of sediments are lithified - they are made into new rocks. Sandstone and limestone are two common sedimentary rocks.
