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Minerals. Chapter 3 Sec. 1 & 2. What Is a Mineral?. A mineral is a naturally formed, inorganic solid that has a definite crystalline structure. All minerals contain one or more of the 92 naturally occurring elements. What is a Mineral?. Answer four questions.
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Minerals Chapter 3 Sec. 1 & 2
What Is a Mineral? • A mineral is a naturally formed, inorganic solid that has a definite crystalline structure. • All minerals contain one or more of the 92 naturally occurring elements.
What is a Mineral? • Answer four questions. • If any answer is “no” – NOT a mineral!
What is a Mineral? • 1) Is it nonliving material? • 2) Is it a solid? • 3) Is it formed in nature? • 4) Does it have a crystalline structure?
What Are Crystals? • Crystals are solid, geometric forms of minerals • Repeating pattern of atoms or molecules creates the crystals • A crystal’s shape is determined by the arrangement of the atoms or molecules within the crystal.
Two Groups of MineralsSilicate vs. Nonsilicate • Silicate Minerals: Minerals that contain a combination of silicon and oxygen molecules. These minerals make up more than 90% of Earth’s crust. Examples: Quartz, Feldspar, and Mica.
Nonsilicate Minerals: Minerals that do not contain a combination of the elements silicon and oxygen. They are made up of carbon, oxygen (without silicon), fluorine, and sulfur. Examples; Copper, Calcite, Fluorite, and Gypsum
Identifying Minerals • There are seven ways to determine the identity of minerals.
Color • Not usually the best way to identify a mineral; for reasons such as impurities.
Luster • The way a surface reflects light; usually described as shiny or dull • Shiny = metallic luster • Dull = submetallic, nonmetallic • Observe samples
Streak • The color of a mineral in powdered form. • A mineral’s streak can be found rubbing the mineral against a piece of unglazed porcelain called a streak plate.
Cleavage and Fracture • Cleavage: the tendency of some minerals to break along smooth, flat surfaces. • Fracture: the tendency of some minerals to break unevenly along curved or irregular surfaces.
This sample of quartz shows a curved fracture pattern called conchoidal fracture.
Hardness • A mineral’s resistance to being scratched. • Scientists use Mohs hardness scale to determine the hardness of minerals. • ***The greater a mineral’s resistance to being scratched is, the higher the mineral’s rating is.
Density • The measure of how much matter is in a given amount of space.
Special Properties • Some minerals can be identified by special properties they have, such as taste (NEVER taste in science class!), magnetism, fluorescence, radioactivity, chemical reaction, and optical properties.
What are Rocks? • Rocks are a combination of one or more minerals.