2. Earth material student notes

Mineralogy: The Study of Minerals and their Properties • A Mineral…

! Occurs _______

! Is a _______

! Is a _______ substance (element or compound)

! Has atoms arrange in an orderly pattern (________)

! Is _________ (not formed by any process involving plants or animals)

• The most common elements that make up minerals are oxygen, silicon,

aluminum, iron, calcium, potassium, and magnesium

• There are over _____known minerals; most are _____.

• Common minerals that make up most of the Earth’s crust are called _____-

_______ MINERALS

• Most minerals are ___________

(i.e., halite = NaCl, Galena = PbS)

• A few minerals are made up of only ONE element, and are called

__________elements

(i.e., gold, copper, silver, sulphur, carbon)

Mineral Identification • Minerals are usually identified using _______ properties, although some

simple _________tests may also be used. IDENTIFICATION BY INSPECTION:

Colour

• First, and most easily ___________ property

• Some minerals have ___________colours (i.e., malachite, sulphur)

• However, many different minerals have _______colours

• ____________may also alter the colour of minerals

Lustre • The way a mineral shines in __________light.

• Either metallic (like polished _______) or non-metallic

• Non-metallic lustre may be further described as _______ (glass-like), pearly,

greasy, dull, earthy, etc.

Crystal Shape

• When minerals have time and room to form, their particles arrange

themselves into flat-faced, regularly shaped _______.

• However, most mineral grains are too small or imperfect to identify.

IDENTIFICATION BY SIMPLE TESTS Streak

• The colour of a mineral’s _______when it is rubbed against a streak plate

• Metallic minerals give _____streaks (brown, grey, black)

• Nonmetallic minerals give _______streaks

Cleavage/Fracture • A mineral exhibits cleavage if it breaks along flat _________ when hit with a

hammer.

• A mineral exhibits fracture if it splits into _______or _______ surfaces.

Hardness • A mineral’s _________to being scratched.

• Moh’s hardness scale: measure of how hard a mineral is compared to a

__________set of minerals, ranging on a scale from 1 to 10 (softest = talc

(1), hardest = diamond (10)).

• Prospector’s Scale: Fingernail = 2.5

Penny = 3

Steel = 5.5

Glass = 6

Specific Gravity

• The relative _______ of a mineral.

• Ratio of mineral’s weight to an equivalent amount of _______.

• Specific gravity of __________minerals is generally < 3

• Specific gravity of _________ minerals is generally > 5

Acid Test

• When calcite is exposed to _______, it fizzes

• Gas produced is _______dioxide

Magnetism

• Some minerals containing iron are _______ and will be attracted to a magnet

(ie., magnetite)

OTHER PROPERTIES:

Taste (i.e., _______ – rock salt)

Fluorescence (glows in _______ light)

Radioactivity

Double __________

Mineral Groups

• All minerals can be classified as either __________ or

_____________minerals

Silicates

• Silicate minerals contain atoms of __________ (Si) and __________ (O)

• Some only contain silicon and oxygen (i.e., ________), but most also

contain one or more other __________ (i.e., feldspar)

• __________is the most common mineral in the earth’s crust, followed by

__________

• Silicates make up ___% of the Earth’s crust

Non-silicates

• 4% of the Earth’s crust is made up of non-silicate minerals (meaning they

don’t contain __________)

• Can be further classified as:

o Carbonates – contain carbonate (CO3) group

o Halides – halogens (Cl, F) with Na, K or Ca

o Native __________

o Oxides – contain __________, but not silicon

o __________– contain sulphate ( (SO4) group

o Sulfides – contain __________

PETROLOGY

The Study of Rocks and their Formation

PRINCIPLES OF UNIFORMITARIANISM:

1. Geological processes now at work were also active in the __________.

2. Physical features of the Earth were formed by these processes over

______ periods of time.

In other words, the rocks we see around us were formed in the past by the

_____ geological processes we see around us today.

Rock Types and the Rock Cycle

• A rock is a __________of minerals bound together (i.e., it is usually a

__________).

• There are three types of rock:

1. igneous rock – formed when ________rock cools

2. sedimentary rock – formed from weathered and eroded rock that is

__________and ________ together into new rock.

3. metamorphic rock – formed when existing rock undergoes intense

_____ and __________ that alters the rock’s composition and

characteristics.

IGNEOUS ROCKS

• “__________” comes from the Greek word for fire.

• Deep inside the earth, the temperature is very high and the rock there is in

liquid form called ________.

• As magma pushes towards the Earth’s __________, it starts to cool and

turn into solid igneous rock.

• Igneous rocks that cool __________ deep in the Earth are called

intrusive or plutonic igneous rocks.

• Other igneous rocks form when magma erupts from a volcano, or reaches

the surface through long cracks in the crust. Magma is called _______

when it reaches the Earth’s surface. These are called extrusive or

volcanic igneous rocks.

• Igneous rocks are classified by __________ (the minerals it contains) and

__________ (crystal size).

Composition of Igneous Rocks

Igneous rocks form from two main types of magma:

• FELSIC: ! Magma with a ______ percentage of silica (SiO2) and little calcium,

magnesium or iron.

! Felsic magma is _______ and slow-flowing

! Forms _______-coloured rocks

! Most __________ rocks are felsic

• MAFIC:

! Magma with a ____ silica content, with higher amounts of calcium,

magnesium and iron.

! Hotter and ________than felsic magma

! Forms ________-coloured rocks

! Most __________rocks are mafic

Texture of Igneous Rocks

• Depends on ______ of mineral crystals in the rock.

• Crystal size depends on how ______ magma hardens

• LONGER = LARGER

• Plutonic rocks cool slower, therefore _______grains

• Lava hardens rapidly forming ______ crystals

• Lava that cools super-quick forms rocks with ___ crystals

• Porphyry: a rock with 2 stages of cooling, so that it has both _______

and ________ crystals.

SEDIMENTARY ROCKS

• most of the earth’s _______ is covered in sedimentary rocks

• there are three types of sedimentary rocks:

a. clastic - made from _______ of other rocks.

b. chemical - formed from precipitates falling out of _______.

c. organic - formed from remains of _______ and _______.

Clastic Sedimentary Rocks

• form when rocks _______ (break apart).

• That material is eroded (_______ away) and later _________ in another

location.

• Layers of sediment undergo __ _____and _________ to eventually form

sedimentary rocks.

• Clastic rocks are classified by “_______” (size of particles)

" Conglomerate: made up of _______ and sand

" Sandstone: mainly _______ of quartz

" Shale: tiny flakes of ____ cemented together

Chemical Sedimentary Rocks

• Form when sea, lake, swamp or underground waters __________ or

change temperature, causing dissolved minerals to fall out of solution.

• Examples include some __________, rock salt and rock gypsum.

Organic Sedimentary Rocks • Formed from the _______of plants and animals

• Shell-producing organisms such as clams, mussels or coral are made up

mostly of _______ – the mineral that makes up limestone. When they die

their shells pile up on the floor of the water body, and eventually

_______together to form limestone.

• Coal is formed from _______ plants that are buried and compacted into

matter that is mostly _______.

Metamorphic Rocks

• _______ and _______ can cause certain minerals to change into other

minerals.

• Mineral crystals may also change in _____ or _____, and may separate

into _______ bands.

• Hot _______ may circulate through a rock, dissolving some minerals and

depositing others.

Types of Metamorphism:

1. Contact metamorphism – when hot magma pushes through _______

rock, causing changes in the structure and composition of

surrounding rock.

2. Regional metamorphism – movement of tectonic plates creates

tremendous ______ and ______ at plate boundaries, changing

minerals into rock.

Classification of Metamorphic Rocks:

• Made according to the texture of the rock (foliated or non-foliated), and the

composition of the rock.

• FOLIATED:

o Extreme pressure _______ mineral crystals in rock and pushes them

into parallel bands

o Minerals of different _______ separate into bands, often producing

alternating dark and light layers.

o Examples included slate, schist and gneiss

• NON-FOLIATED: o No “banding” or _______ are observed

o Examples include quartzite and marble

o

Rock Cycle