Minerals and Their Economic Importance

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Questions and Answers

What type of mineral is obsidian classified as?

Volcanic glass (correct)

Amorphous graphite

Lignite

Crystalline silica

Which of the following is considered a primary mineral?

Apatite (correct)

Calcite

Galena

Clay minerals

Which mineral is known for its use in electric cables?

Halite

Feldspar

Copper (correct)

Iron

What characterizes secondary minerals?

Result of alteration of primary minerals Signup and view all the answers

Which of the following is a copper ore mineral?

Malachite Signup and view all the answers

What determines a mineral's suitability as an ore mineral?

The ease of separation from gangue Signup and view all the answers

What is the primary use of feldspar?

Glass and ceramics Signup and view all the answers

Which mineral requires the least energy to smelt?

Sulfide minerals Signup and view all the answers

What are the two main groups of minerals based on color and composition?

Mafic and Felsic Signup and view all the answers

What term refers to the worthless minerals associated with ore minerals?

Gangue Signup and view all the answers

Which of the following is a property used to identify minerals?

Color Signup and view all the answers

Which mineral is known for its single, perfect cleavage?

Mica Signup and view all the answers

What characteristic shape is described by the term 'Euhedral'?

Well-developed crystal faces Signup and view all the answers

Which of the following minerals is a source of aluminum?

Bauxite Signup and view all the answers

What term is used for a mineral habit composed of slender, needle-like crystals?

Acicular Signup and view all the answers

Which of the following minerals is commonly used in cosmetics?

Talc Signup and view all the answers

What is the primary purpose of conducting a flame test?

To differentiate between elements based on their emission spectrum Signup and view all the answers

Which acid can be used to clean the wire loop before a flame test?

Hydrochloric acid Signup and view all the answers

Which of the following tests is NOT used to discriminate between calcite and dolomite?

Feigl test Signup and view all the answers

How is aragonite identified during the Meigen test?

By observing a gradual color change to lilac Signup and view all the answers

What is indicated by the presence of carbonate minerals in rocks?

Major constituents of sedimentary rocks Signup and view all the answers

Which test can differentiate between Magnesite and Smithsonite?

Friedman test Signup and view all the answers

What happens to the wire loop before each flame test?

It must be cleaned to prevent contamination Signup and view all the answers

Which test is associated specifically with the discrimination of aragonite?

Meigen test Signup and view all the answers

What is the chemical formula for cyclosilicates like Tourmaline?

[SinO3n]2n- Signup and view all the answers

Which type of silicate structure is associated with Pyroxene?

Single Chain Signup and view all the answers

Which of the following minerals has a sheet structure?

Mica (Muscovite) Signup and view all the answers

What primarily determines the hardness of a mineral?

Internal arrangement of the mineral's atoms Signup and view all the answers

Which property can help distinguish between calcite and quartz?

Acid drop test Signup and view all the answers

Which statement is NOT true about minerals?

They can be organic substances. Signup and view all the answers

The chemical formula for olivine indicates that ______.

magnesium and iron can substitute for one another Signup and view all the answers

What type of mineral shows variable color?

Allochromatic Signup and view all the answers

Which of the following is not an essential condition for hydrothermal deposits?

Highly inactive fluids Signup and view all the answers

What is the most common metamorphic mineral mentioned?

Garnet Signup and view all the answers

In which tectonic setting does regional metamorphism occur?

Convergent plate boundaries Signup and view all the answers

What shape does the silicate tetrahedron (SiO4)4- resemble?

Pyramid Signup and view all the answers

Which group of silicate minerals is characterized by independent tetrahedral structures?

Nesosilicates Signup and view all the answers

Graphite converts to diamond under what conditions?

High temperature and high pressure Signup and view all the answers

What type of metamorphism is primarily caused by contact with magma?

Contact metamorphism Signup and view all the answers

What is the base unit of silicate minerals?

SiO4 Signup and view all the answers

Study Notes

Mineral Classification and Properties

Obsidian: Volcanic glass, non-crystalline (amorphous).
Jet: Organic lignite, a precursor to coal, non-crystalline.
Opal: Amorphous silica with chemical composition SiO2·nH2O.

Economic Importance of Minerals

Copper: Used for electric cables, wires, and switches.
Feldspar: Utilized in glass, ceramics, and sanitary ware.
Calcite: Found in toothpaste, construction, and antacid tablets.
Iron: Major component in buildings, magnets, and cars.
Halite: Commonly known as table salt, used in food preservation.
Graphite: Employed in electrical applications, pencils, and lubricants.

Mineral Groups

Rock-forming Minerals: Abundant minerals in various rocks, divided into:
- Primary Minerals: Crystallized directly from magma or lava, including essential (define rock) and accessory (do not define rock) minerals.
  - Essential examples: Feldspar, quartz, biotite.
  - Accessory examples: Zircon, sphene, apatite (major source of phosphorus).
- Secondary Minerals: Formed by the alteration of primary minerals through weathering/hydrothermal processes (e.g., clay minerals).
Ore-forming Minerals: Minerals suitable for metal extraction.
- Examples: Hematite (Fe2O3 - iron), galena (PbS - lead), malachite (Cu2(CO3)(OH)2 - copper), native gold (Au).

Factors Affecting Ore Minerals

Suitability determined by:
- Ease of separation from gangue and concentration for smelting.
- Energy required to release metals from mineral bonds; sulfide, oxide, or hydroxide minerals require less energy to smelt than silicate minerals.

Mafic and Felsic Minerals

Mafic Minerals: Rich in iron and magnesium, generally dark-colored (e.g., olivine, pyroxene).
Felsic Minerals: Light-colored (e.g., quartz, feldspar).

Gangue and Metallic Minerals

Gangue Minerals: Non-valuable minerals associated with ore minerals.
Metallic Minerals: Sources of metals such as iron, aluminum, copper, and more.

Industrial Minerals

Mined for physical properties such as hardness, color, and luster.
Applications include abrasives (garnet), cosmetics (calcite, talc), and agricultural uses (phosphates).

Mineral Nomenclature

Mineral names based on physical properties, chemical composition, locality, or mineralogist.
Examples include:
- Albite: Named for its white color (Latin: albus).
- Chromite: Contains chromium.

Mineral Identification Techniques

Identified by physical properties (color, luster, hardness) or advanced methods (XRD, chemical analysis).
Test methods include flame tests, where a clean wire loop is dipped into a sample to observe emission colors.

Carbonate Minerals

Key constituents of sedimentary rocks, also found in igneous and metamorphic rocks.
Identification assists via chemical staining and various discrimination tests (e.g., between calcite and dolomite).

Silicate Minerals Classification

Silicate minerals are the most common on Earth; classified into 7 sub-groups based on their silicate anion structure:

Nesosilicates: Independent tetrahedra (e.g., Olivine).
Sorosilicates: Double tetrahedra (e.g., Epidote).
Inosilicates: Single-chain (e.g., Pyroxene) and double-chain (e.g., Amphibole).
Phyllosilicates: Sheet structure (e.g., Mica).
Tectosilicates: 3D frameworks (e.g., Feldspar, Quartz).

Metamorphism and Its Types

Metamorphism occurs under high temperature and pressure, transforming existing rocks.
Common metamorphic minerals: garnet and serpentine.
Types of metamorphism:
- Contact Metamorphism: High temperature, low pressure, driven by nearby magma.
- Regional Metamorphism: High temperature and pressure over large areas, usually at convergent plate boundaries.

Important Mineral Tests

Tests for differentiating minerals include specific reactions with chemical solutions (e.g., Lemberg test for calcite and dolomite) and response to thermal tests for emissions in flame.

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Description

This quiz covers various minerals, including obsidian, jet, opal, and their characteristics. It also explores the economic importance of minerals like copper, feldspar, calcite, iron, halite, and graphite. Test your knowledge about the properties and uses of these vital resources.