Mineral and Rock Identification Assignment -

Purpose: The purpose of this lab is for students to become familiar with the basic properties of rocks and minerals through identifying several different rocks and minerals based on their properties.

Equipment supplied: Rock and mineral samples, Streak plate, Glass plate, Penny

Part 1 - Mineral Identification

You will identify minerals based on their physical properties. A mineral is a naturally occurring substance with a definite chemical composition and characteristic structure. Minerals differ from each other in both chemical composition and physical properties.

Color is the most obvious property, but is highly variable; descriptions include dominate color as well as additional colors.

Luster is a description of how light is reflected off of the mineral and is typically described as either metallic or non-metallic.

Hardness is a measure of how solid the mineral is and is classified using the Mohs Hardness Scale (1 = softest, 10 = hardest).

Streak is the color of the mineral powder left behind on a streak plate.

Other miscellaneous properties include grain size, crystal size, feel, taste, magnetism, etc.

1. Use the physical properties of the samples, Table 1. Mohs Hardness Scale, and Table 2. Physical Properties of Minerals to identify the minerals.

Part 2 - Rock Identification

Rocks are composed of two or more minerals and can be classified as igneous, sedimentary, or metamorphic based on origin. Igneous rocks form when magma rises from the mantle, cools, and hardens either below the Earth's surface or on the surface. Sedimentary rocks are layered accumulations of mineral particles derived from weathering and erosion of preexisting rocks, chemical deposition, or accumulation of plant and animal remains. Metamorphic rocks form when igneous, sedimentary, or other metamorphic rocks are subjected to intense heat and pressure to form

Igneous Rock Identification

Igneous rocks can be subdivided based on whether they formed above or below the Earth's surface. Intrusive igneous rocks form by gradually cooling below the surface, which results in the formation of large crystal grains. Extrusive igneous rocks form by cooling rapidly at the Earth's surface, which results in small crystal grains and often contain pockets of air.

2. Use the physical properties of the samples and Table 3. Physical Properties of Igneous Rocks to identify the igneous rocks.

Sedimentary Rock Identification

Sedimentary rocks can be subdivided based on the source of minerals. Clastic sedimentary rocks, the most common sedimentary rocks, form from the accumulation of mineral grains weathered from other rocks (e.g., sandstone). Chemically-precipitated sedimentary rocks form from minerals precipitated from solution or from organism that build shells from minerals dissolved in solution (e.g., limestone). Organic sedimentary rocks form from the accumulation of organic material; coal, asphalt/bitumen, lignite, and oil shale are examples of organic sedimentary rocks.

3. Use the physical properties of the samples and Table 4. Physical Properties of Sedimentary Rocks to identify the sedimentary rocks.

Metamorphic Rock Identification

All rocks can be subjected to metamorphic processes, so a wide variety of metamorphic rocks exist. Metamorphic rocks form when a pre-existing rock is subjected to intense heat and pressure to chemically and/or physically alter the rock into a new rock type (e.g., limestone being metamorphosed into marble). Metamorphosis occurs when rocks are deeply buried and compressed by overlying material, along plate boundaries and fault lines, during mountain uplift, and near volcanoes and other regions of invading magma. Metamorphic rocks are often smoother, harder, and have more banding compared to their parent rocks.

4. Use the physical properties of the samples and Table 5. Physical Properties of Metamorphic Rocks to identify the metamorphic rocks.

5. Which of the following can be scratched by a nail?

a. quartz

b. sapphire

c. gypsum

d. diamond

6. Which mineral was the most difficult to identify and why?

7. Which of the different characteristics of a mineral seem the most useful in identification and why?

8. How are igneous rocks subdivided?

9. How are sedimentary rocks subdivided?

10. How do metamorphic rocks typically compare to their parent rocks?

Note - All tables are attached.

Attachment:- Assignment Files.rar