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Minerals Chapter 9 Section 1.

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Presentation on theme: "Minerals Chapter 9 Section 1."— Presentation transcript:

1 Minerals Chapter 9 Section 1

2 Learning Objectives Identify the difference between a mineral and a rock Describe the properties that are used to identify minerals Each mineral has a set of physical properties that can be used to identify it

3 New Vocabulary Mineral Rock Crystal Gem Ore

4 What is a mineral? Where are they found?
Are they in a cave? Or in a mine? Minerals can be found anywhere and everywhere! What are some examples of minerals? Pencils (graphite), salt, metal pots, glassware, ceramic dishes

5 What is a Mineral? Minerals: inorganic, solid materials found in nature Inorganic: usually not formed by plants or animals Minerals often have a beautiful crystal shape The particular chemical makeup and arrangement of the atoms in the crystal is unique to each mineral Rocks: usually made of two or more minerals

6 Minerals Each mineral has a unique characteristics that is used to identify it Over 4,000 minerals have been identified so far

7 How do minerals form? There are several ways minerals form:
Melted rock material in Earth (Magma) As it cools, atoms combine in orderly patterns to form minerals Also form as magma reaches Earth’s surface (lava)

8 How do Minerals form? 2. Evaporation forms minerals
Salt crystals appear when seawater evaporates; other dissolved minerals can crystallize 3. Precipitation can form minerals Water can hold only so much dissolved material Extra separates and falls out as solid To figure out how a mineral was formed, you have to look at the size of the mineral crystal and how the crystals fit together

9 Properties of Minerals
Each mineral has a set of physical properties than can be used to identify it We will discuss 6 properties of minerals that are helpful in identifying them Crystals: solid materials that have a repeating pattern of atoms Pyrite commonly forms crystals with 6 faces

10 Properties of Minerals
Cleavage and Fracture The way a mineral breaks can help identify it Splits into pieces with smooth, regular panes that reflect light = cleavage Minerals that break into pieces that are jagged or have rough edges = fracture

11 Properties of Minerals
3. Color: Sometimes a minerals color can help figure out what it is Color can also fool you! (Fool’s gold is pyrite) The same mineral can occur in a variety of colors Calcite in figure 5 pg 271

12 Properties of Minerals
4. Streak & Luster Streak: The color of the powered form of a mineral If a mineral is rubbed across an unglazed, white tile, (streak plate) it produces a streak of color Sometimes the streak is different than the color of the mineral Luster: describes how light reflects off the mineral’s surface Is it shiny, dull, pearly, glassy, or earthy Metallic minerals = shiny like a metal Nonmetallic minerals = pearly, glassy, dull or earthy

13 Properties of Minerals
Hardness Some minerals are harder than others Soft ones like talc can be scratched with fingernails Hard ones like diamonds are so hard they can be used to cut almost anything else Mohs scale: classifies minerals on a scale of 1 (softest) to 10(hardest) Use one mineral to scratch another to see which on is harder

14 Properties of Minerals
Specific Gravity Some minerals are heavier than others Specific gravity compares the weight of a mineral with the weight of an equal volume of water Fool’s gold is 5 times heavier than water; real gold is 19 times heavier than water Easily tell this by holding each in your hand

15 Other Properties There are other properties that can help identify minerals Magnetite will attract to a magnet Calcite will fizz when it comes into contact with acids Some scientists will taste minerals to identify them (YUCK!!)

16 Common Minerals There are over 4,000 minerals that make up most rocks
“rock-forming minerals” Most rock-forming minerals are silicates They contain the elements silicon and oxygen Quartz is pure silica Feldspar (type of silicate mineral) makes up ½ rocks Carbonates are another type of important rock-forming minerals Made of carbon and oxygen Calcite is a carbonate

17 Common Minerals Other common minerals can be found in rocks that formed at the bottom of ancient seas as they evaporated Gypsum is abundant in many places Halite or rock salt is found in large quantities in the Midwest

18 Gems Gems are minerals that are rare and can be cut and polished
Must be clear with few or no blemishes or cracks Must have beautiful luster or color Very few minerals meet these standards Gems are very rare and valuable

19 Making A Gem Gems are rare because they are formed under special conditions Diamonds are forms of the element carbon Diamonds can be made in a lab setting or they are formed deep within Earth’s mantle Volcanic eruptions bring diamonds to the surface for miners to find Pg 274 figure 9

20 Ores A mineral is called an ore if it contains enough of a useful substance that it can be sold for profit Many metals that we use come from ores Iron used to make steel Lead used to make batteries Magnesium in vitamins Extracted from Earth’s surface by mining

21 Conserving Ores Scrap metal recycled or reused to decrease mining
Ores take millions of years to form so they are considered a non-renewable resource Mining can disrupt environments, landscapes, use valuable resources and increase production costs

22 Ore Processing After mining, ore must be processed to extract the desired mineral or element Copper goes through a process called smelting After this process, copper can be refined or purified Then it can be processed into many materials Sheet metal, electrical wiring, cookware, etc…

23 Review Questions Explain the difference between a mineral and a rock. What are 5 common rock-forming minerals? (pg 273 for minerals that form rocks) List 5 properties that are commonly used to identify minerals. Describe an event that must occur in order for diamond to reach Earth’s surface. Where in Earth is diamond formed? Would you want to live close to a gold mine? Explain why or why not.

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