Week 4: an intro to minerals

What is a mineral?

A naturally occurring chemical substance with a definite atomic structure and chemical formula.

What are the characteristics of minerals?

Minerals are crystalline, solid, inorganic materials.

How many naturally occurring minerals are there on Earth?

About 5700.

What is the most abundantly occurring mineral on Earth?

Quartz (SiO2).

What distinguishes minerals from non-minerals?

Minerals are solid and crystalline, while non-minerals like glass are amorphous.

What are the five most common classes of rock-forming minerals?

Silicates, carbonates, oxides, sulfides, and sulfates.

What is the chemical formula for calcite?

CaCO3.

What is the process of mineral formation through cooling and crystallization?

Minerals crystallize from molten rock as it cools.

What is the significance of silicate tetrahedra in mineral formation?

Silicate tetrahedra are the building blocks of silicate minerals.

What is Bowen's reaction series?

A concept that explains how minerals crystallize from a melt at different temperatures, changing the composition of the remaining melt.

What is the Si:O ratio in isolated tetrahedra silicates?

1:4.

What is the Si:O ratio in single chain silicates?

1:3.

What is the Si:O ratio in double-chain silicates?

4:11.

What is the Si:O ratio in sheet silicates?

2:5.

What is the Si:O ratio in 3D framework silicates?

1:2.

What determines the color of a mineral?

The chemical composition, including ions and trace elements.

What is the Mohs scale of hardness?

A scale that ranks minerals from 1 (talc) to 10 (diamond) based on hardness.

What is cleavage in minerals?

Planes of weakness in a mineral related to its atomic structure.

What is the difference between organic and inorganic minerals?

Organic minerals contain carbon from living organisms, while inorganic minerals do not.

What are the main physical properties used to identify minerals?

Color, lustre, hardness, habit, and cleavage.

What is the chemical formula for quartz?

SiO2.

What are the two types of carbonates mentioned?

Calcite (CaCO3) and aragonite.

What is the role of aluminum in the Earth's crust?

Aluminum (Al) constitutes 8.1% of the crust.

What is the significance of the silicate ion?

The silicate ion (SiO4) has a negative charge and can bond with cations to form minerals.

What is the definition of a mineral?

A naturally occurring, solid, crystalline substance, usually inorganic, with a specific chemical composition.

What does the term 'cleavage' refer to in minerals?

The tendency of a mineral to break along irregular surfaces other than cleavage planes.

How does bond strength relate to cleavage in minerals?

Cleavage varies inversely with bond strength; weak ionic bonds lead to good cleavage, while strong covalent bonds result in poor or no cleavage.

What is Mohs hardness scale?

A scale that ranks minerals based on their hardness, from 1 (talc) to 10 (diamond).

What is the significance of streak in mineral identification?

Streak is the color of the mineral in powdered form, which can help distinguish between minerals with similar appearances.

What mineral is known for its effervescence when reacting with acid?

Calcite (CaCO3).

What is the primary component of the mineral Halite?

Sodium chloride (NaCl).

What is the difference between igneous, sedimentary, and metamorphic rocks?

Igneous rocks form from molten rock, sedimentary rocks form from erosion and deposition of pre-existing rocks, and metamorphic rocks form from changes due to heat and/or pressure.

What is lithification?

The process of turning sediment into rock.

What are the two main textures of igneous rocks?

Coarse-grained (slow cooling) and fine-grained (fast cooling).

What is the chemical composition of felsic igneous rocks?

Rich in silica and low in magnesium and iron, typically containing quartz and feldspar.

What is the primary characteristic of mafic igneous rocks?

Poor in silica and rich in magnesium and iron, typically containing minerals like biotite and pyroxene.

What is the role of impurities in quartz?

Impurities can cause variations in the color of quartz, such as smoky quartz being brown to grey opaque.

What is the significance of crystal habit in minerals?

Crystal habit refers to the characteristic shape of a mineral's crystals, which can aid in identification.

What is the diagnostic color of Malachite?

Green, due to its copper content.

What does the term 'density' in minerals depend on?

The atomic weight of atoms or ions and their closeness of packing in the crystal structure.

What type of mineral is Magnetite?

An oxide mineral known for its magnetic properties.

What is the definition of a rock?

A naturally occurring aggregate of mineral grains or non-mineral solid matter.

What is the process of crystallization in silicate minerals?

Silicate minerals crystallize from a melt, extracting certain elements and changing the chemical composition of the melt.

What is the significance of the term 'outcrop' in geology?

An outcrop refers to the natural exposure of bedrock at the Earth's surface.

What are pyroclasts?

Volcanic materials such as ash, pumice, and bombs ejected during eruptions.

What type of rocks are formed from lava cooling rapidly?

Extrusive igneous rocks.

What are the two main types of igneous rocks?

Extrusive and intrusive igneous rocks.

What is the difference between extrusive and intrusive igneous rocks?

Extrusive rocks cool rapidly and are fine-grained, while intrusive rocks cool slowly and are coarser-grained.

What is an example of an extrusive igneous rock?

Basalt or rhyolite.

What is an example of an intrusive igneous rock?

Gabbro or granite.

What are the main categories of sedimentary rocks?

Clastic, biogenic, and chemical.

What are clastic sedimentary rocks made of?

Fragments of pre-existing rocks transported and deposited by physical processes.

What are biogenic sedimentary rocks?

Rocks formed from the remains of living organisms, such as limestone and coal.

What are chemical sedimentary rocks?

Rocks that precipitate directly out of water, such as evaporites.

What is diagenesis?

The processes that occur during lithification.

What does the term 'weathering' refer to?

The breakdown of rocks through mechanical and chemical processes.

What is the weathering series?

A ranking of minerals based on their stability and susceptibility to weathering.

Which mineral is the least stable and most easily weathered?

Olivine.

What is the most stable mineral according to the weathering series?

Quartz.

What is metamorphism?

The process by which rocks are changed by heat and/or pressure.

What happens to limestone during metamorphism?

It transforms into marble.

What happens to sandstone during metamorphism?

It transforms into quartzite.

What is the Rock Cycle?

The process by which igneous, sedimentary, and metamorphic rocks are related and transformed through geological processes.

What are the three types of rocks classified by their origin?

Igneous, sedimentary, and metamorphic.

What is the significance of the Rock Cycle?

It illustrates the interactions between plate tectonics and climate systems.

What is the primary composition of sedimentary rocks in terms of Earth's crust?

Sedimentary rocks make up about 5% of the Earth's crust but cover about 75% of its surface.