Minerals—The Building Blocks of Rocks - The Changing Earth: Exploring Geology and Evolution - page 60

OUTLINE
Introduction
Matter—What Is It?
Explore the World of Minerals
Mineral Groups Recognized by Geologists
GEO-INSIGHT: The Precious Metals
Physical Properties of Minerals
GEO-FOCUS: Welcome to the Wonderful World of Micas
Rock-Forming Minerals
How Do Minerals Form?
Natural Resources and Reserves
Geo-Recap

OBJECTIVES
At the end of this chapter, you will have learned that
All matter, including minerals, is made up of atoms that bond
to form elements and compounds.
Geologists have a specifi c defi nition for the term mineral.
You can distinguish minerals from other naturally occurring
and manufactured substances.
Minerals are incredibly varied, yet only a few are particularly
common.
Geologists use physical properties such as color, hardness, and
density to identify minerals.
Minerals originate in various ways and under varied
conditions.
Some minerals, designated rock-forming minerals, are par-
ticularly common in rocks, whereas others are found in small
amounts.
Some minerals and rocks are important natural resources that
are essential to industrialized societies.

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In this specimen of polished agate, multi-colored rings surround a central
mass of tiny quartz crystals. Agate forms by fi lling a hollow inside a host rock,
and as a result it is often found with concentric bands that resemble tree
rings.

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