Chapter 2 Minerals – Study Guide
Section 1 – Minerals
Minerals – naturally occurring, inorganic, solid with a definite chemical composition and
crystal structure.
1. Naturally occurring – all minerals are formed by natural processes which occur on or
Inside the Earth with no input from humans.
2. Inorganic – not made up of once living things (plants/animals)
Exception: diamonds and graphite which are made up of carbon atoms
3. Solid – have a definite volume and shape (no gases or liquids)
4. Crystalline structure – Crystalline means that atoms are arranged in a pattern that is
repeated over and over again.
*There are 6 major crystal systems (Ex. Halite = cubic)
5. Definite Chemical Composition – all minerals are an element or compound
Example: Halite (NaCl= sodium chloride = salt) is made up of sodium and chlorine
Gold is a mineral made of only the element gold (Au)
Crystal = a solid in which the atoms are arranged in orderly, repeating patterns.
Crystals form from:
1. Magma – The type and amount of elements present in a magma partly determine
which minerals will form. The size of the crystals that form depends partly on how
rapidly the magma cools. (ex. Amethyst)
*when magma cools slowly, crystals are large
*when magma cools quickly, crystals are small
2. Salt solutions – When water evaporates, ions that are left behind can come together to
form crystals. (Ex. Halite)
Section 1 – Mineral Identification
Physical properties of minerals help us identify minerals. Some of these physical properties
are color, hardness, streak, luster, specific gravity, cleavage and fracture, and other special
properties.
Hardness – A measure of how easily a mineral can be scratched.
In 1812 the Mohs scale of mineral hardness was devised by the German mineralogist Frederich Mohs
(1773-1839), who selected the ten minerals because they were common or readily available. The
scale is not a linear scale, but somewhat arbitrary.
Hardness
Mineral
Hardness of common objects
1
Talc
2
Gypsum
Fingernail (2.5)
3
Calcite
Piece of copper (2.5-3.0)
4
Fluorite
Iron nail (4.5)
5
Apatite
Glass (5.5)
6
Feldspar
Steel file (6.5)
7
Quartz
Streak plate (7.0)
8
Topaz
The November birthstone. Emerald and aquamarine
are varieties of beryl with a hardness of 8.
9
Corundum
Sapphire and ruby are varieties of corundum. Twice
as hard as topaz.
10
Diamond
Used in jewelry and cutting tools. Four times as hard
as corundum.
*Talc is the softest mineral and diamond is the hardest mineral*
Streak – When a mineral is rubbed across a piece of unglazed porcelain tile, a streak of
powdered mineral is left behind. Streak is the color of a mineral in powdered form.
*the streak test only works for minerals that are softer than the streak plate (hardness of 7)
*graphite is soft enough to leave a streak on paper (pencil)
*gold and pyrite can be distinguished because gold has a yellow streak and pyrite has a
greenish-black or brownish-black streak
Luster – the way a mineral reflects light.
*luster can be metallic (galena) or non-metallic (quartz)
*non-metallic lusters include dull, pearly, silky and glassy
*some common minerals with a glassy luster are quartz, calcite, halite, and fluorite
Specific Gravity – the ratio of its weight compared with the weight of an equal volume of
water. Specific gravity is expressed as a number.
Example: the specific gravity of gold is about 19 and the specific gravity of pyrite is 5. This
means that gold is about 19 times heavier than water and pyrite is 5 times heavier than water.
If you compared equal-sized samples of gold and pyrite, the pyrite would feel much lighter in
your hands.
Cleavage and Fracture – the way a mineral breaks.
Cleavage - Minerals that break along smooth, flat surfaces have cleavage. (Ex. Mica)
Fracture – Minerals that break with uneven, rough, or jagged surfaces have fracture. (Ex.
Quartz)
Other properties:
Magnetite = is attracted to magnets
Lodestone = a form of magnetite, will pick up iron filings like a magnet
Calcite = you can see a double image when viewed through a transparent sample of calcite;
calcite also fizzes when hydrochloric acid is put on it.
Chapter 2 Section 3 – Uses of Minerals
Gems – or gemstones are highly prized minerals because they are rare and beautiful.
*most gems are special varieties of a particular mineral. They are clearer, brighter, or more
colorful than common samples of the mineral.
Example: Amethyst is a gem form of quartz that contains just traces of iron to give it a purple
color.
Common Mineral
Gem Example
Beryl
Emerald
Spinel
Ruby
Olivine
Peridot
Quartz
Amethyst
Corundum
Blue Sapphire
Gem
Use
Diamond
Industrial abrasives/cutting tools
Ruby
Produce specific types of laser lights
Quartz
Electronics and clocks/watches
Useful Gems:
*Gems are highly prized mineral specimens often used as decorative pieces in jewelry or
other items.
*Some gems have industrial uses.
Useful Elements in Minerals:
Ores = a mineral or rock containing a useful substance that can be mined at a profit.
Example: Iron is used in everything from frying pans to ships and is obtained from its ore,
hematite. Iron from Hematite
Example: Aluminum from Bauxite
Example: Titanium is used in automobile body parts, aircraft, eyeglass frames, sports
equipment and bicycles. Titanium is obtained from the minerals Rutile and Ilmenite.
*Iron, aluminum, zinc, and titanium are common metals that are extracted from minerals
Vocabulary:
Cleavage
Crystal
Fracture
Gem
Hardness
Inorganic
Luster
Magma
Mineral
Ore
Specific gravity
Streak
What will the Chapter 2 Test look like?
1.)
2.)
3.)
4.)
5.)
12 matching – the 12 vocabulary words (12 points)
12 True/False – based of vocabulary and facts from study guide (12 points)
12 multiple choice – based on study guide facts and using hardness scale (12 points)
3 Short Answer – see below (9 points)
5 Fill in the blank – (using a word bank) - (5 points)
Test = 50 points
Interactive Workbook = 60 points
Cover Page – Creatively design a cover based on what you learned in Chapter 2
5 pts
must include colored illustrations
Page 1 – must include complete definition and a minimum of 2 reasons why minerals
2 pts
are important
Page 2 – define or explain each term – must include a minimum of 1 colored illustration 5pts
Page 3 - define or explain each term – must include a minimum of 1 colored illustration 5pts
Page 4 - table must be completed neatly and include the definition of crystal on page
5pts
Page 5 – should include a sketch under #1
1 pt
Page 6 – not graded
Page 7 – table must be completed
2pts
Page 8 – include the two ways that crystals form and describe
4pts
Page 9 – complete definition and list
2pts
Page 10 - define or explain each term – must include a minimum of 1 colored illustration 5pts
Page 11 - define or explain each term – must include a minimum of 1 colored illustration 5pts
Page 12 – define hardness and complete table
5pts
Page 13 - define or explain each term – must include a minimum of 1 colored illustration 5pts
Page 14 – must include at least 5 specific uses of minerals and a minimum of 1 colored
illustration
5pts
Page 15 – Complete chart
4 pts
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Return the bottom portion only!! Thank you!
I have seen the study guide for Chapter 2 Minerals and the requirements for the Interactive
Workbook. I understand that the test is on Thursday, November 6th and the Interactive
Workbook is due that same day.
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