Minerals

Minerals

naturally occurring, inorganic solids with a definite chemical composition and a specific crystalline structure

Mineral

has a unique internal arrangement of
atoms that gives it distinct properties.

Minerals

considered the
fundamental building blocks of
rocks and, in turn, of Earth’s crust.

Minerals

dentified and classified based on their physical
and chemical properties

Physical Properties

features that can be observed or
measured without changing the mineral’s identity.

Color

• Visible appearance of the mineral
• Can sometimes be misleading due to impurities

Streak

Color of the mineral in powdered form, obtained by rubbing it on a streak plate

Often more reliable than surface color

Luster

How the mineral reflects light.

Metallic or Non-Metal

Hardness

Mineral’s resistance to scratching

Measured using the Mohs Hardness Scale

Mohs Hardness Scale

ranks the relative hardness of minerals from 1 to 10

Cleavage

Tendency of a mineral to break along smooth, flat
surfaces or planes

Zones of weaknesses are aligned

Fracture

How minerals break irregularly or unevenly when cleavage is absent, often producing uneven or jagged surfaces

Zones of weaknesses are not aligned

Specific Gravity

ratio of a mineral’s weight to the weight of an equal volume of water.

Unitless

Density

an object’s mass per unit volume.

Has units

Crystal Form

The external shape of a mineral.

reflects its internal atomic structure.

Chemical Properties

mineral’s chemical composition and how it reacts with other substances

Reaction to Acid

Some minerals such as calcite react with dilute hydrochloric acid (HCl)

Oxidation

Reaction with oxygen, often causing color changes

Solubility

Whether a mineral can dissolve in water or other liquids

Chemical Composition

What elements make up the mineral

Related to the main mineral group

Silicates

Largest and most abundant group, making up about 90% of Earth’s crust; characterized by SiO₄

Examples: quartz, feldspar, mica, olivine

Carbonates

Contain carbon and oxygen in the form CO₃^2-

Examples: calcite, dolomite

Oxides

Minerals where oxygen is bonded to one or more metals
Examples: hematite, magnetite, corundum

Sulfates

Contain the sulfate ion SO₄^2-
Examples: gypsum, barite

Phosphates

Contain the phosphate group PO₄^3-

Halides

Formed with halogen elements combined with metals
Examples: halite, fluorite

Native Elements

Occur in pure form as single elements

Examples: gold, copper, silver, diamond (pure carbon)

Rocks

naturally occurring, solid, inorganic aggregate of one or more minerals.

Rocks

do not have a definite chemical composition or a specific crystal structure.

Igenous Rocks

when molten material cools and solidifies.

They make up most of Earth’s crust and provide clues about volcanic activity.

Examples: granite, basalt, pumice, obsidian

Intrusive (Plutonic) Igneous Rocks

Form beneath Earth’s surface from slowly cooling magma

Crystals grow large, producing a coarse-grained texture

Example: granite, diorite, gabbro

Extrusive (Volcanic) Igenous Rocks

Form on Earth’s surface from rapidly cooling lava.

Crystals remain small or even invisible, producing a fine-grained or glassy texture.

Example: basalt, obsidian, pumice

Sedimentary Rocks

form when particles of rock, minerals, or organic matter are deposited, compacted, and cemented.

They often show layering (strata) and may contain fossils.

Examples: sandstone, limestone, shale, chalk, dolomite,
coal.

Clastic Sedimentary Rocks

Made from compacted fragments of other rocks

Example: sandstone, conglomerate, shale

Chemical Sedimentary Rocks

Formed from the precipitation of dissolved minerals

Example: limestone, halite, gypsum

Organic Sedimentary Rocks

Formed from accumulated biological matter

Example: coal

Metamorphic Rocks

created when existing rocks undergo changes due to high heat, pressure, or chemical processes.

Examples: marble (from limestone), slate (from shale), quartzite, schist, gneiss

Foliated Metamorphic Rocks

Have visible layers or bands due to mineral alignment

Example: slate, schist, gneiss

Non-Foliated Metamorphic Rocks

Do not show layering

Usually uniform in texture

Example: marble, quartzite

Chemical Layers of Earth

Crust, Mantle, Core

Crust

Outermost and thinnest layer

Composed mainly of silicate rocks; granite and basalt.

Continental Crust

thicker, less dense, made mostly of granitic rocks.

Oceanic Crust

thinner, denser, made mostly of basaltic rocks.

Thickest Layer

Composed mainly of silicate minerals rich in iron and magnesium (e.g., peridotite)

Makes up about 84% of Earth’s volume

Convection currents

are the driving force behind plate tectonics.

Core

Composed primarily of iron and nickel

Outer Core

liquid layer; movement of molten metal here produces Earth’s magnetic field.

Inner Core

solid due to immense pressure, despite extreme temperatures exceeding 5,000 °C.

Mechanical Layers

Based on Physical Properties

Lithosphere

Rigid outer layer, about 100 km thick

Includes the crust and the uppermost portion of the mantle

Broken into tectonic plates that float on the softer layer beneath

Asthenosphere

Semi-solid, ductile layer of the upper mantle beneath the lithosphere

Allows the lithospheric or tectonic plates to move and shift

Lower Mantle

Also sometimes called as mesosphere

More rigid than the asthenosphere due to higher pressure

Still capable of very slow flow, transmitting seismic waves effectively

Outer Core

Liquid layer composed mainly of molten iron and nickel

Movement within this layer generates Earth’s magnetic field

Inner Core

Solid sphere with a radius of about 1,220 km.

Remains solid because of extreme pressure, even though temperatures are as high as the Sun’s surface

Chondrites (stony meteorites)

Contain primitive, undifferentiated material comparable to the early mantle composition.

Iron meteorites

Thought to be fragments of planetesimal cores, rich in iron and nickel, analogous to Earth’s metallic core.

Plate Tectonics

unifying theory in geology explaining the movement of large tectonic plates on Earth’s surface.
his movement is driven by mantle convection, ridge push, and slab pull.

Tectonic Plates

large, rigid sections of the lithosphere which includes Earth’s crust and the
uppermost solid part of the mantle

Plate Boundaries

The edges where tectonic plates interact.

the most geologically active regions on Earth.

Convergent Boundary

Plates move toward each other.

Oceanic-Continental

Forms subduction zones, volcanic arcs, strong earthquakes (e.g., Andes Mountains)

Oceanic-oceanic

Forms island arcs, deep-sea trenches (e.g., Mariana Trench)

Continental–continental:

Forms mountain ranges (e.g., Himalayas)

Oceanic-Continental

oceanic plate will always subduct

oceanic-oceanic

denser oceanic plate will always subduct

Continental-continenal

no subduction occurs, large mountain range forms

Transform Boundary

Plates slide past each other without creating or destroying crust

Characterized by strong earthquakes

Little or no volcanic activity