Minerals rock identify a mineral

Minerals are important because:We use them in everyday life!. Minerals are important because:We use them in everyday life!. • Glass Quartz • Lead in pencil Graphite ©McGill University 20

Minerals ROCK!

This presentation was made possible with funding from the

PromoScience programme of NSERC

Why are they important?

©McGill University 2010

Minerals are important because:

We use them in everyday life!

• Glass (Quartz)

Minerals are important because:

We use them in everyday life!

• Glass (Quartz)

• Lead in pencil (Graphite)

©McGill University 2010www.public-domain-image.com

Minerals are important because:

We use them in everyday life!

• Glass (Quartz)

• Lead in pencil (Graphite)

• Toothpaste (Fluorite)

Minerals are important because:

We use them in everyday life!

• Glass (Quartz)

• Lead in pencil (Graphite)

• Toothpaste (Fluorite)

• Coins and wiring (Chalcopyrite, from which

most copper metal is made)

©McGill University 2010

www.public-domain-image.com and www.wikipedia.org Public domain

Minerals are important because:

We use them in everyday

life!

• Glass (Quartz)

• Lead in pencil (Graphite)

• Toothpaste (Fluorite)

• Coins and wiring

(Chalcopyrite, from which most copper metal is made)

• White paint (Rutile and

Ilmenite)

Minerals are important because:

We use them in everyday life!

• Glass (Quartz)

• Lead in pencil (Graphite)

• Toothpaste (Fluorite)

• Coins and wiring (Chalcopyrite,

from which most copper metal

Minerals are important because:

We use them in everyday life!

• Makeup (Talc, Muscovite)

• Jewellery (Gold, Silver,

Platinum…)

• How many minerals are there in the world?

– Over 4200 different minerals!

– But only 100 are common

• Ones that are more rare include:

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www.wikipedia.org Public domain

What does this mean?

• A mineral must have…

– A crystalline structure

• Minerals are made of molecules, and a crystalline structure is a repeated pattern of those molecules.

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Crystalline structure (i)

– The crystalline structure explains the geometric

shapes that crystals take on when they grow

under favourable conditions

Crystalline structure (ii)

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• Crystals will keep growing…

Crystalline structure (iii)

… and growing forever, as long as they have the chemical elements and the environmental

conditions necessary.

Minerals are formed by geological

processes

– They can’t be man-made so steel

is not a mineral.

©McGill University 2010www.wikipedia.org Public domain

Minerals are inorganic

– Not living and not made by living things.

– Shells are not a type of mineral but they they are made of solid materials (biominerals) similar to

some inorganic minerals.

A mineral is solid

– Minerals may be dissolved in liquids but they

themselves are not liquid.

©McGill University 2010www.wikipedia.org

Is ice a mineral? (i)

Is ice a mineral? (ii)

Ice in your ice-cube tray

is not naturally occurring:

ice in a glacier is.

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Is water a mineral? (i)

www.usgs.gov Public domain.

Is water a mineral? (ii)

How are minerals formed?

• Many minerals crystallize from liquids,

principally magma/lava (molten rock), hot

waters (e.g., geysers), or oceans

• Others are formed when rocks are re-buried

below the Earth’s surface and exposed to high pressure and temperature The minerals

become unstable and they exchange chemical elements This forms new minerals

Why are minerals found in large

quantities in some places and not

others?

• The Earth’s surface is made up of plates that move “Plate tectonics” describe this motion.

• Together with erosion, plate tectonics

concentrate some of these elements in

bodies of rocks that can be mined.

• Plate tectonics are the Earth's giant "recycling engine“.

Plate tectonics

The world’s main plates

©McGill University 2010www.wikipedia.org Public domain

Types of plate boundaries (i)

• Transform boundaries: plates grind past each

other along a transform fault (e.g San

Andreas fault).

Types of plate boundaries (ii)

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• Divergent boundaries: plates slide away from

each other (e.g., mid-oceanic ridges).

Wikipedia.org, NASA: public domain

Types of plate boundaries (iii)

• Convergent

boundaries: plates

slide towards each

other

– If one plate moves

underneath the other, it

forms a subduction zone

Deep marine trenches,

volcanoes, and some

mountain chains (e.g., the

North American plate

Caribbean plate

Types of plate boundaries (iv)

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• Convergent boundaries (cont’d):

– If the two plates collide and both contain

continental crust, they form a continental collision Some mountains (e.g., the Himalayas) form this

way

Wikipedia.org, USGS: public domain

Rocks

• Rocks are made of minerals

• Granite is a rock made up of three main

Igneous rocks

©McGill University 2010www.wikipedia.org Public domain

• Deep in the earth the temperatures are so high that materials, including minerals, melt and form magma.

• When the magma cools, it becomes rock.

• E.g., granite, basalt.

Metamorphic rocks (i)

• When rocks are re-buried below the Earth’s

surface and exposed to high pressure and

temperature, the minerals become unstable and they exchange chemical elements

• This forms new minerals This may also

cause some grains to grow and others to

shrink.

Metamorphic rocks (ii)

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Gneiss

Slate

www.usgs.gov Public domain

• This process produces new types of rocks

that are different in composition and

texture from the originals

• E.g., bands of minerals are folded in gneiss.

Sedimentary Rocks

• Sediments come from the erosion of

previously existing rocks, dissolved

minerals that precipitate out of

solution, or the remains of plants

and animals.

• Loose sediment accumulates in beds and, over time,

becomes compressed and cemented together.

• These types of rocks are

usually layered

• E.g., limestone and sandstone.

Sandstone1

The Rock Cycle: Always Recycling

©McGill University 2010www.wikipedia.org Public domain

Quartz

Halite

What is the difference between

minerals, crystals, and rocks? (i)

– Minerals are made up of regularly arranged

– Crystals are made up of only one type of mineral.

– A crystal’s atoms, ions, or molecules are arranged

in an orderly, repeating pattern.

– Crystals can have different shapes, depending on

how the groups of atoms are arranged.

Quartz crystal and penny

What is the difference between

minerals, crystals, and rocks? (ii)

What is the difference between

minerals, crystals, and rocks? (iii)

How are crystals formed?

• Most come from a liquid evaporating (e.g., salt)

or magma cooling.

• Minerals in the liquid precipitate

out as the liquid evaporates As

more minerals precipitate out,

the crystal grows in size

• Crystals can grow forever, as long as they have the chemical elements and the environmental conditions necessary.

Mineral Identification (i)

• The two most important properties that

scientists use to identify minerals are:

– chemical composition (e.g., via microprobe

analysis)

– crystal structure (e.g., via X-ray diffraction

analysis), which is reflected in the mineral's

crystal symmetry and shape

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Mineral Identification (ii)

• Other properties that scientists use to help

identify minerals include:

– Colour

– Luster (how the surface reflects light)

– Streak (the mark it leaves on a ceramic plate)

– Hardness

– Magnetism

– Crystal system (crystal shape and the way in

which the crystals are arranged)

• Scientific consultation

• Concept, design, and production:

– This presentation was made possible with funding

from the PromoScience

programme of NSERC

©McGill University 2010