69 Minerals, Rocks, and Soil-Low

Minerals, Rocks, and Soil Written by Rachel Kamb

Introduction Earth has everything you need to stay alive. It has water, air, plants, and animals. Earth also has land! Land is where you walk and play. Your home sits on land, too. What is land made of? Why is it important? In this book, you will learn about nonliving Earth materials that make up the land. Nonliving materials come in many colors and shapes. They come in many sizes, too. They can change in many ways.

Elements and Minerals Let's start with elements. They make up everything on Earth They are very, very small. Do You Know? Elements are not the smallest parts of matter. The tiniest bits of each element are called atoms.

A mineral is made of elements. Minerals are solid and inorganic They were never alive. Some minerals have just one element. For example, silver is just made of silver. Iron is only made of iron Other minerals, such as quartz, have two or more elements. Earth has about 4,000 kinds of minerals. Each mineral has its own mix of elements.

Rocks A rock is made of minerals. It is hard solid and natural. A rock can have many colors and patterns. The bits and pieces of minerals give a rock its colors and patterns.

Look at the chart. It shows you many ways to compare rocks. HOW TO DESCRIBE AND COMPARE ROCKS Mineral composition Rocks have a special mix of minerals. Size Rocks can be huge boulders or small pebbles. They can be as big as a mountain or as tiny as a speck of dust. Shape Rocks can be flat, round, square, or almost any other shape. Color Rocks come in every color you can imagine. Many rocks have more than one color. It depends on the colors of their minerals. Texture Some rocks are rough while others are smooth. They can have tiny grains or large, smooth chunks. Some have long crystals. Others are full of airholes. Hardness The Mohs Scale of Hardness compares how hard each mineral is within a rock. Talc is rated a 1 (very soft), and diamonds are rated a 10 (very hard). Patterns Rocks may have streaks, waves or lines. They may have dots or be built layer upon layer. Some rocks do not have a clear pattern. Location An important way to describe a rock is by where you find it. A beach may have different rocks than a forest, desert, or volcano.