Mineralogy Basics

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Questions and Answers

Which of the following is an example of a carbonate mineral?

Gibbsite

Calcite (correct)

Apatite

Hematite

What is the primary characteristic of the native elements class of minerals?

Composed of oxygen and hydrogen

Contains sulfides and selenides

Made of just a single element bonded to itself (correct)

Composed of carbonates

Which mineral belongs to the sulfates class?

Pyrite

Barite (correct)

Bornite

Gibbsite

Which class includes minerals that are composed of the silicate tetrahedron (SiO4)?

Silicates Signup and view all the answers

Identify the mineral that is categorized as an oxide.

Cuprite Signup and view all the answers

Which of the following minerals is an arsenate?

Cornetite Signup and view all the answers

Which mineral is considered a sulfide?

Pyrite Signup and view all the answers

What type of minerals does the phosphate class contain?

Phosphates, arsenates, vanadates, and antimonates Signup and view all the answers

What characteristic shape of a mineral unit is referred to as crystal form habit?

The observable shape of a mineral Signup and view all the answers

Which mineral is known for its hardness and ability to scratch all other substances?

Diamond Signup and view all the answers

What does the term 'streak' refer to in mineral identification?

The powdered color of the mineral Signup and view all the answers

Which property describes a mineral's ability to break along preferred planes?

Cleavage Signup and view all the answers

What is meant by 'specific gravity' when discussing minerals?

The density ratio of the mineral to water Signup and view all the answers

Which of the following describes a mineral that is easily broken by cleaving?

Fragile Signup and view all the answers

What is a characteristic of a mineral classified as ductile?

Can be drawn into wires without breaking Signup and view all the answers

Which mineral is known for having a salty taste?

Halite Signup and view all the answers

What defines a mineral?

It is made up of one or more chemical elements. Signup and view all the answers

What does luster refer to in minerals?

The way light is reflected from the surface. Signup and view all the answers

Which mineral is the softest according to the Mohs scale?

Talc Signup and view all the answers

Which of the following has a Mohs hardness of 5?

Apatite Signup and view all the answers

What can scratch a steel nail according to the Mohs scale?

Quartz Signup and view all the answers

What is the role of Friedrich Mohs in mineralogy?

Created a hardness scale for minerals. Signup and view all the answers

Which mineral can scratch quartz?

Corundum Signup and view all the answers

What happens when a fingernail scratches gypsum?

It scratches easily. Signup and view all the answers

Study Notes

Definition of Minerals

Minerals are naturally occurring inorganic elements or compounds.
They possess a definite chemical composition and orderly internal structure.
Distinction from rocks: unlike rocks, minerals cannot be decomposed into smaller units with different chemical compositions.

Physical Properties of Minerals

Luster: Refers to the reflection of light off a mineral's surface.
Hardness: A measure of a mineral's resistance to scratching, developed in the Mohs scale by Friedrich Mohs over 100 years ago.
- Mohs hardness scale ranges from 1 (talc) to 10 (diamond).
- Talc is the softest mineral; diamond is the hardest, capable of scratching all substances.

Mohs Hardness Scale

Talc: 1, easily scratched by a fingernail; used in talcum powder.
Gypsum: 2, can be scratched by a fingernail; ingredient in plaster.
Calcite: 3, scratched by a copper penny; used in cement.
Fluorite: 4, scratched by a steel nail; used in toothpaste.
Apatite: 5, scratchable by a steel nail; found in bone.
Feldspar: 6, can scratch glass; used in glass-making.
Quartz: 7, can scratch steel and glass; used in glass and electronics.
Topaz: 8, can scratch quartz; a gemstone.
Corundum: 9, includes rubies and sapphires; scratchable by very hard materials.
Diamond: 10, the hardest mineral.

Crystal Form and Habit

Represents the characteristic shapes of mineral units, whether individual crystals or groups.

Color and Streak

Color: Often the most visible characteristic but least diagnostic due to variations.
Streak: The powdered form color of the mineral, useful for identifying minerals. Hematite, for example, produces a reddish-brown streak.

Cleavage and Fracture

Cleavage: The ability of a mineral to break along preferred planes; can have 1 to 6 cleavage planes.
Fracture: Irregular breakage of a mineral, unlike cleavage.

Specific Gravity

Reflects the "heaviness" of a mineral, calculated as the ratio of the mineral's weight to the weight of an equal volume of water (water has a specific gravity of 1).

Other Identifying Properties

Magnetism: Some minerals like magnetite are strongly magnetic.
Odor and Taste: Sulfur has a distinctive smell; halite is salty.
Reaction to Acid: Calcite fizzes with acid.
Tenacity: Describes toughness:
- Fragile: Easily broken (e.g., sulfur).
- Malleable: Can be flattened into sheets (e.g., gold).
- Ductile: Can be drawn into wires (e.g., copper).
- Sectile: Can be cut into shavings (e.g., gypsum).
- Flexible: Can be bent without breaking (e.g., molybdenite).
- Elastic: Returns to original shape after bending (e.g., micas).

Classification of Minerals

Based on chemical composition:
- Metals: e.g., chromium
- Non-metals: e.g., diamond, graphite
- Metalloids: e.g., brass, iron-nickel
Native Elements: Comprised of single elements bonded to themselves.

Examples of Mineral Classes

Carbonates: e.g., calcite (CaCO3), cerussite (PbCO3).
Nitrates: e.g., niter (KNO3).
Phosphates: e.g., apatite.
Oxides: e.g., hematite (Fe2O3).
Sulfates: e.g., barite.
Sulfides: e.g., pyrite.

Common Rock-Forming Minerals

Minerals with noteworthy physical and chemical properties used in geological studies and applications.

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Description

Explore the fundamental concepts of minerals, including their composition, structure, and properties. This quiz covers essential terminology such as luster and hardness. Perfect for students learning about geology and minerals.