Earth's MAterials

Rocks are our oldest ancestors. They are all related! They are made from minerals. Minerals are made from chemicals: aluminum, potassium, and silicon. Some minerals are organic and come from plants and animals. Organic materials from plants, animals, and trees rot and get compressed over time. There are hundreds of minerals. Minerals harden and, when polished, look like black glass! There are hundreds of minerals. Minerals are measured by their hardness or softness on a scale of 1-10. The softest mineral is talc, and the hardest is a diamond. Look out across the land. Imagine the ground cover, grasses, plants, and trees covering everything before people arrived. Hundreds of minerals create hundreds of different kinds of rocks.

Rocks, believe it or not, are younger than the Earth! Some rocks heat and melt, mixing with other minerals and crystals and forming new liquid rock. These are igneous rocks, or rocks that melt and make new rocks over and over. Rocks that are compressed and heated can also change their form and color. These rocks are known as metamorphic rocks, or rocks that change over time. Metamorphic rocks can pick up other minerals and crystals over time, changing shape and color. Rocks wear down into smaller pieces, such as grains of sand, pebbles, insect and animal fossils, shell fragments, and sea creature remains, which are squashed in layers and cemented, creating sedimentary rock. Frozen water and flowing rivers erode rocks and move them into the sea, where they join with sand and mud, sink to the bottom, and eventually harden into sedimentary rocks. The high heat of Earth’s core melts rocks underground into Magma. As magma and lava cool, they form into volcanic rocks of many shapes and sizes.