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Front of Digital Textbook
Table of Contents
1. What is Earth Science?
1.1 The Nature of Science
1.2 Earth Science and Its Branches
2. Studying Earth's Surface
2.1 Earth’s Surface
2.2 Where in the World Are You?
2.3 Modeling Earth’s Surface
2.4 Topographic Maps
2.5 Using Satellites and Computers
3 Earth’s Minerals
3.1 Matter Matters
3.2 Minerals and Mineral Groups
3.3 Mineral Identification
3.4 Mineral Formation
3.5 Mining and Mineral Use
4.1 Types of Rocks
4.2 Igneous Rocks
4.3 Sedimentary Rocks
4.4 Metamorphic Rocks
5 Earth’s Energy
5.1 Energy Resources
5.2 Non-renewable Energy Resources
5.3 Renewable Energy Resources
6. Plate Tectonics
6.1 Inside Earth
6.2 Continental Drift
6.3 Seafloor Spreading
6.4 Theory of Plate Tectonics
7.1 Stress in the Earth’s Crust
7.2 Nature of Earthquakes
7.3 Measuring and Predicting Earthquakes
7.4 Staying Safe in Earthquakes
8.1 Where Volcanoes Occur
8.2 Volcanic Eruptions
8.3 Types of Volcanoes
8.4 Volcanic Landforms and Geothermal Activity
9. Weathering and Formation of Soil
10. Erosion and Deposition
10.1 Water Erosion and Deposition
10.2 Wave Erosion and Deposition
10.3 Wind Erosion and Deposition
10.4 Glacial Erosion and Deposition
10.5 Erosion and Deposition by Gravity
11. Evidence About Earth’s Past
11.2 Relative Ages of Rocks
11.3 Absolute Ages of Rocks
12 Earth’s History
12.1 Early Earth
12.2 The Precambrian
12.3 Phanerozoic Earth History
12.4 History of Earth’s Complex Life Forms
13. Earth’s Fresh Water
13.1 Water on Earth
13.2 Surface Water
13.3 Ground Water
14. Earth’s Oceans
14.1 Introduction to the Oceans
14.2 Ocean Movements
14.3 The Seafloor
14.4 Ocean Life
15. Earth’s Atmosphere
15.1 The Atmosphere
15.2 Atmospheric Layers
15.3 Energy in the Atmosphere
15.4 Air Movement
16.1 Weather and Atmospheric Water
16.2 Changing Weather
16.4 Weather Forecasting
17.1 Climate and Its Causes
17.2 World Climates
17.3 Climate Change
18. Ecosystems and Human Populations
18.2 Lesson Objectives
18.3 The Carbon Cycle and the Nitrogen Cycle
18.4 Human Populations
19. Human Actions and the Land
19.1 Loss of Soils
19.2 Pollution of the Land
20. Human Actions and Earth’s Resources
20.1 Use and Conservation of Resources
20.2 Energy Conservation
21. Human Actions and Earth’s Waters
21.1 Humans and the Water Supply
21.2 Problems with Water Distribution
21.3 Water Pollution
21.4 Protecting the Water Supply
22. Human Actions and the Atmosphere
22.1 Air Pollution
22.2 Effects of Air Pollution
22.3 Reducing Air Pollution
23. Observing and Exploring Space
23.2 Early Space Exploration
23.3 Recent Space Exploration
24. Earth, Moon, and Sun
24.1 Planet Earth
24.2 Earth’s Moon
24.3 The Sun
24.4 The Sun and the Earth-Moon System
25. The Solar System
25.1 Introduction to the Solar System
25.2 Inner Planets
25.3 Outer Planets
25.4 Other Objects in the Solar System
26. Stars, Galaxies, and the Universe
26.3 The Universe
27. Earth Science Glossary
28. Maine Learning Results
29. Download ES in PDF Format
30. Download Individual Chapters
3.4 Mineral Formation
Describe how melted rock produces minerals.
Describe how hot rock produces different minerals.
Explain how minerals form from solutions.
Minerals form under an enormous range of geologic conditions. There are probably more ways to form minerals than there are types of minerals themselves. Minerals can form from volcanic gases, sediment formation, oxidation, crystallization from magma, or deposition from a saline fluid, among others. A few of these will be discussed below.
Formation from Hot Material
is a collection of minerals. Imagine a rock that becomes so hot it melts. Many minerals start out in liquids that are that hot.
is melted rock inside Earth, a molten mixture of substances that can be hotter than 1,000oC. Magma cools slowly inside Earth and so mineral crystals have time to grow large enough to be seen clearly (
Granite with different minerals labeled.
Granite is rock that forms from slowly cooled magma, containing the minerals quartz (clear), plagioclase feldspar (shiny white), potassium feldspar (pink), and biotite (black).
When magma erupts onto Earth's surface, it is called
. Lava cools much more rapidly than magma. Mineral crystals do not have time to form and so are very small. The chemical composition will be the same as if the magma cooled slowly.
Existing rocks may be heated enough that the molecules are released from their structure and can move around. The molecules may match up with different molecules to form new minerals as the rock cools. This occurs during metamorphism, which will be discussed in the Rocks chapter.
Formation from Solutions
Water on Earth, such as the water in the oceans, contains chemical elements mixed into a solution. Various processes can cause these elements to combine to form solid mineral deposits.
Minerals from Salt Water
When water evaporates, it leaves behind a solid precipitate of minerals, as shown in
When the water in glass A evaporates, the dissolved mineral particles are left behind.
Water can only hold a certain amount of dissolved minerals and salts. When the amount is too great to stay dissolved in the water, the particles come together to form mineral solids, which sink. Halite easily precipitates out of water, as does calcite. Some lakes, such as Mono Lake in California (
) or The Great Salt Lake in Utah, contain many mineral precipitates.
Tufa towers form when calcium-rich spring water at the bottom of Mono Lake bubbles up into the alkaline lake. The tufa towers appear when lake level drops.
Minerals from Hot Underground Water
Magma heats nearby underground water, which reacts with the rocks around it to pick up dissolved particles. As the water flows through open spaces in the rock and cools, it deposits solid minerals. The mineral deposits that form when a mineral fills cracks in rocks are called
Quartz veins formed in this rock.
When minerals are deposited in open spaces, large crystals form (
Amethyst formed when large crystals grew in open spaces inside the rock. These special rocks are called geodes.
Mineral crystals that form when magma cools slowly are larger than crystals that form when lava cools rapidly.
Minerals form when rock is heated enough that atoms of different elements can move around and join into different molecules.
Minerals are deposited from salty water solutions on Earth’s surface and underground.
Under what circumstances do large crystals form from a cooling magma?
Under what circumstances do small crystals form from a cooling magma?
What happens to the mineral particles in salt water when the water evaporates?
Explain how mineral veins form.
Further Reading / Supplemental Links
Gems and Where They’re Found:
How to Grow Your Own Crystals:
vein Minerals that cooled from a fluid and filled cracks in a rock rocks Mixtures of minerals. magma Molten rock deep inside the Earth. lava Molten rock that has reached the Earth's surface.
Points to Consider
Is a mineral a static thing or does it change? If it changes, on what time frame?
When most minerals form, they combine with other minerals to form rocks. How can these minerals be used?
The same mineral can be formed by different processes. How can the way a mineral forms affect how the mineral is used?
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