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Chapter 4: Section1 What Are Minerals?
Minerals – a naturally occurring, inorganic solid that has a crystal structure and a definite chemical composition
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What 5 Characteristics Does a Mineral Have to Have?
A mineral must be: Naturally Occurring Inorganic Solid Crystal Structure Definite Chemical Composition
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What Does It Mean to Be Naturally Occurring?
A mineral must occur naturally Cement, brick, steel, and glass all come from substances found in Earth’s crust but they are manufactured by people
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How Can Something Be Inorganic?
Inorganic – the mineral cannot arise from materials that were once part of a living thing Ex. Coal is NOT a mineral because it is made up the remains of plants and animals
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What kind of pattern must a mineral have?
A mineral must have a crystal structure – a repeating pattern of a mineral’s particles that forms a solid. Faces – a crystal’s flat side that meets at sharp edges and corners
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What kind of composition must a mineral have?
A mineral must have a definite chemical composition – it always contains certain elements in definite proportions; most minerals are compounds Cinnabar – composed of the elements Mercury and Sulfur
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What Is the Difference Between an Element and a Compound?
Element – a substance composed of a single kind of atom. Ex. Hydrogen Compound – Two or more elements combined so that the elements no longer have distinct properties Ex. Water H20
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How Do You Identify Minerals?
Properties: Density Crystal Shape Cleavage and Fracture Special Properties Hardness Color (this can vary) Streak Luster
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How Do You Determine a Mineral’s Hardness?
Friedrich Mohs invented a test to describe and compare the hardness of minerals Mohs Hardness Scale Ranks ten minerals from softest to hardest
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How Does the Mohs Scale Work?
Gypsum (2) will scratch talc (1), calcite (3) will scratch gypsum (2), fluorite (4) will scratch calcite (3), etc.
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The streak of a mineral is the color of its powder
What Is a Streak Test? The streak of a mineral is the color of its powder The streak color and the mineral color are often different To test: rub a mineral against an unglazed tile (streak plate)
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What is the Luster of a mineral?
Luster – used to describe how a mineral reflects light from its surface Minerals containing metals are often shiny Earthy, waxy, and pearly
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What does Density have to do with Minerals?
Each mineral has a characteristic Density Density – or mass per unit volume; Density = mass/volume Displacement – the volume of the displaced water equals the volume of the the sample
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What Kind of Shape does a Mineral have?
Minerals have a crystal structure Cubic Hexagonal Tetragonal Orthorhombic Monoclinic Triclinic
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What is Mineral Cleavage?
Cleavage – A mineral’s ability to split easily along a flat surface The ability to break apart depends on the arrangement of the atoms in the mineral Cubic Cleavage Basal Cleavage
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What is Mineral Fracture?
Fracture – How a mineral looks when it breaks apart in an irregular way
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What Special Properties does a Mineral have?
Fluorescence –minerals that glow under ultraviolet light Magnetism - ex. Loadstone Chemical Reactivity- ex. Calcite gives off carbon dioxide Electrical Properties – ex. quartz
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Section2: How are Minerals Formed?
Two General Ways: Crystallization of melted materials Minerals from Magma Crystallization of materials dissolved in water Minerals from Hot water solutions Minerals formed by evaporation
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What is Crystallization?
the process by which atoms are arranged to form a material with a crystal structure
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How do Minerals form from Magma?
Minerals form as magma cools inside the crust, or as lava hardens on the surface
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What Effects Crystal Size?
Rate at which magma cools Slower cooling forms larger crystals The amount of gas the magma contains The chemical composition of the magma
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How do Minerals Form from Hot Water Solutions?
Magma beneath Earth’s surface has heated the water to a high temperature beneath Earth’s surface causing minerals to dissolve When this solution cools the elements and compounds leave the solution and crystallize as minerals
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Solution – A mixture in which one substance dissolves in another
What is a Solution? Solution – A mixture in which one substance dissolves in another
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What do Pure Metals often form from Hot Water Solutions?
Veins – A narrow channel or slab of a mineral that is much different from the surrounding rock
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How are Minerals Formed by Evaporation?
As water turns to vapor it leaves behind the mineral Example: A salt water solution leaves behind large crystals of salt
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Where are Minerals Found?
Earth’s crust is made up of a variety of minerals however; rare and less common minerals are usually located near plate boundaries because of volcanic activity and mountain building
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Section 3: How are Minerals Used?
Minerals are the source of Metals ex. Aluminum, Iron Gemstones ex. Rubies and Sapphires Other Useful materials ex. Talc (talcum powder)
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Now show me your completed notes and I will give you your webquest-keep the laptop
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