Rocks and Minerals / Породы и минералы

One of the nine known planets that revolve around the Sun, the Earth is thought to be about 4.6 billion years old. Geology is the study of the history of the Earth. Because rocks can provide valuable information about the Earth in previous times, geologists study them and work out the processes and events that produced them. As we can currently bore only a few miles into the crust, or outer shell, we cannot sample rocks from the mantle (the inner shell) directly. The rocks and minerals shown here come from many locations and introduce important features that are explained in more detail later in the book.