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1 What is a mineral? H.E.3A.5 Analyze and interpret data to describe the physical and chemical properties of minerals and rocks and classify each based on the properties and environment in which they were formed.

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3 What is a Mineral? Geologists rely on several relatively simple tests to identify minerals. These tests are based upon a mineral s physical and chemical properties.

4 What is a Mineral? By using the results from a combination of tests rather than just one, the mineral s classification and identity is more accurate. Comparing test results from the mineral sample with known properties of minerals from a mineral identification chart increases the accuracy of the identification.

5 Minerals Minerals are naturally occurring, inorganic, uniform materials that have definite chemical and physical properties. Minerals can be found in soil and rocks. The properties of minerals are used to determine the kind of minerals.

6 Two Properties Physical Properties Examples: hardness luster color texture streak cleavage/fracture density specific gravity Chemical Properties Examples: ability to burn reactivity to acids

7 Cleavage When a mineral sample is broken with a hammer, it breaks along planes of weakness that are part of its crystalline structure. These breaks are cleavages. Some structures for example can be cubic or hexagonal,.

8 Color Some minerals can be identified by their colors. However, color alone can not be used to identify a mineral. Chemical impurities can change a mineral s color.

9 Hardness A mineral s hardness is determined by the ability of one mineral to scratch another. The Mohs scale is used to tell how hard a mineral is. The scale rates the hardness of minerals from 1 to 10.

10 Luster Luster is the way the surface of a mineral reflects light. There are two general types of luster : metallic and nonmetallic. Nonmetallic luster is described as glassy, pearly, waxy and earthy/dull.

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12 Streak When a mineral is rubbed onto a hard, rough, white surface it will leave a streak of the mineral in powdered form. A minerals streak will always be the same color.

13 Texture The texture of a mineral describes the way it feels. Gritty minerals feel sandy while waxy minerals feel smooth and sticky.

14 Density Rock density is a physical characteristic that is governed by the chemical composition and pore spaces of a specific rock or rock type.

15 Specific Gravity Defined as the ratio of the mass of a substance to the mass of an equal volume of water at 4C

16 Minerals Most rock forming minerals are silicates (contain silicon and oxygen). Quartz is pure silica. Other rock forming minerals are carbonate (contains carbon and oxygen).

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18 Minerals, Rocks & Layers of the Earth

19 Minerals These are natural, inorganic solid materials found on Earth that are the building blocks of rock. Each has a certain chemical makeup and set of properties that determine their use and value.

20 Earth's Resources Minerals, ores, and fossil fuels are considered Earth s resources. They have properties that make them important and useful. The two types of properties are physical and chemical.

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22 Classifications of Rocks Igneous Rocks Sedimentary Rocks Metamorphic Rocks

23 Igneous Rocks Forms when molten rock (magma) cools and hardens If cooling takes place slowly beneath Earth s surface, the igneous rock is called Intrusive. Example: Basalt If cooling takes place rapidly on Earth s surface, the igneous rock is called Extrusive. Example: Granite

24 Sedimentary Rocks Forms from the compaction (being pressed) &/or cementation (being glued) of rock pieces, mineral grains, or shell fragments called sediments. Sediments are formed through the processes of weathering and erosion of rocks exposed at Earth s surface. Also formed by precipitation (the chemical depositing of materials that were once dissolved in water).

25 Metamorphic Rocks Forms when rocks are changed into different kinds of rock by great heat &/or pressure. The rocks are heated, squeezed, folded, or chemically changed by contact with hot fluids.

26 Rock Cycle This is an on going process. It is a series of natural processes that recycles rock material. Rocks are constantly changing form from one kind to another.

27 Rock Cycle Metamorphic Rocks Igneous Rocks Sedimentary Rocks

28 Layers of the Earth Crust made up of soil, rocks,and mountains and is very thin (5 to 60 km thick) the least dense layer overall Two different types: Oceanic Crust: thinnest crust and very dense rock such as basalt Continental Crust: thickest crust and less dense rock such as granite solid rock is composed of silicon and oxygen

29 Layers continued Mantle Is very hot rock and nearly 3,000 km thick Lithosphere: upper portion of the mantle and the crust and is very rigid Asthenosphere: beneath the lithosphere and can bend and flow Its density increases with depth because of increasing pressure. It contains softened rock; contains iron and magnesium.

30 Layer continued Core nearly 3,450 km thick which is almost the size of Earth s moon and is the hottest layer The most dense layer It has two parts: Outer core: molten metals (nickel and iron) which act as a thick liquid Inner core: solid dense ball of nickel and iron The inner core spins slightly faster than the earth. This creates Earth s magnetic field.

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