This document provides an overview of minerals and how to identify them. It begins by listing learning objectives about mineral crystals, characteristics, composition, and connections to rocks. Key points include: minerals have definite compositions and ordered atomic structures; many minerals contain similar elements; and rocks contain multiple minerals. The document then discusses several tests to identify minerals, such as color, hardness using Mohs scale, luster, streak, cleavage, density, and acid/magnetic reactions. Common mineral properties, uses, and identification characteristics are summarized in tables. The document emphasizes that minerals are naturally occurring solids composed of elements, and form through various geologic processes.

1. UNIT 6: MINERALS

2. After Unit 6 you should be able to:
o Understand how mineral crystals acquire their shape
o Understand the characteristics that define a sample as a mineral
o Understand that many minerals are composed of similar elements
o Understand the connections between minerals and rocks and that
many rocks contain similar minerals
o Utilize the ESRT to determine human uses of common minerals
o Understand and be able to perform common mineral identification
tests such as:
o Color
o Streak
o Breakage (cleavage or fracture)
o Hardness (Mohs Scale)
o Acid test
o Magnetism test
o Luster
o Density

3. o Element
o Atom
o Chemical Composition
o Mineral
o Rock
o Organic
o Inorganic
o Orderly arrangement
o Solidification
o Lava
o Magma
o Igneous
o Precipitate
o Evaporate
o Sedimentary
o Metamorphic
o Crystallize
o Crystal
o Appearance
o Hardness
o Mohs Scale
o Luster
o Metallic
o Non-metallic
o Streak
o Powdered
o Crushed
o Breakage
o Cleavage
o Fracture
o Density
o Mass
o Volume
o Acid
o Reaction
o Magnetic
o Abrasive
o Lubricant
Unit 6 vocabulary you should be able to use and understand:
o Scratch
o Impurities
o Oxidation
o Angular
o Physical properties
o Chemical properties

4. Atoms and Minerals
 All matter is made up of atoms
 Each atom has particles within it that make it
a specific element such as gold or calcium
 Atoms bond together to create molecules
 Enough of specific molecules bonded
together form a mineral
 Some minerals contain impurities (other
molecules or elements) that change their
properties such as color

5. 5 Fundamental Mineral Characteristics
 Definite chemical composition
 Orderly arrangement of atoms
 Naturally occurring
 Inorganic
 Solid

6. What is a mineral?
 Minerals have a definite chemical
composition unique to that
mineral
 Many times the chemical properties
a mineral possesses determines
what humans use that mineral for
 For example, the mineral gibbsite
(Al(OH)3) can be processed to
release the aluminum atoms within
it to be used in manufacturing

7. Mineral Composition and
Uses
 Use your ESRT page 16

8. Definite Chemical Composition
 The same elements will make up the same
minerals but impurities/oxidation may at
times change their color
 For example, table salt, or halite, is always
NaCl…composed of a combination of sodium
(Na) and chlorine (Cl) atoms

9. Other Mineral Uses
 Jewelry
 Electronics
 Abrasives
 Lubricants
 A source of metal (ore)/other useful
elements

10. What are minerals made up of?
 Minerals are composed of 1 or more
elements
 Certain elements contribute color to
minerals (such as these quartz
samples), but color alone is not a
definite way of identifying them
 Many minerals contain the same
elements
 Use your ESRT to identify the
elements after you have determined
the mineral

11. Common Mineral Uses
 Use your ESRT page 16

12. Orderly Arrangement of Atoms
 Atoms are arranged in an orderly fashion so
that a crystal forms
 This arrangement defines a mineral’s
physical properties such as crystal shape,
hardness, or cleavage
 For example: halite crystals and the atoms
that produce them

13. Atomic Arrangement and Breakage
 The bonds between atoms (internal atomic
arrangement) in a given mineral determine
how the mineral breaks
 Even, angular breakage is known as
cleavage
 Uneven, rough breakage is known as
fracture
 The cleavage of the mineral graphite allows it
to slide off in sheets when pressure is applied,
thus making it ideal as a material in pencil
lead.

14. Naturally Occurring/Inorganic Solid
 Was not produced by life processes or
humans
 Is not a liquid or a gas

15. How do minerals form?
 Minerals crystals form due to one
of several rock-forming processes
found in the rock cycle
 Cooling and solidification of
magma/lava
 Precipitating out of a solution
 Evaporation, leaving the
minerals behind
 Undergoing heat and/or pressure
to form new minerals

16. Rocks are made up of 1 or more minerals
 This granite has several minerals
within it

17. Identifying minerals can be difficult,
however many minerals can be identified
with a combination of simple tests.
Mineral Identification: Appearance (color)
 Color and appearance can help identify
some minerals, but it is usually not
enough
 Many minerals have multiple colors
or have the same color as other
minerals
 Crystal shape can also help identify a
mineral
Gold
Pyrite

18. Common Colors
 Use your ESRT page 16

19. Mineral Identification: Hardness
 Hardness is a measure of how easily a
mineral can be scratched
 Hard minerals are able to scratch
glass while soft minerals do not
 Talc is a very soft mineral and can be
scratched by a fingernail
 Diamonds are the hardest naturally
occurring material and can only be
scratched by another diamond

20. Mineral Identification: Mohs Scale
 The Mohs Scale uses a number to
describe a mineral’s hardness
 A diamond is a ’10’ since it is the
hardest mineral
 Talc, being one of the softest, is
assigned a ‘1’
 Lower numbers  more easily
scratched

21. Hardness Values of Common
Minerals
 Use your ESRT page 16

22. Mineral Identification: Luster
 The luster of a mineral describes how
a sample reflects light
 Metallic luster is when a mineral
appears to be made of metal
 Non-metallic luster can be a variety of
other colors including minerals that
look like glass

23. Luster of Common Minerals
 Use your ESRT page 16

24. Mineral Identification: Streak
 The streak of a mineral is the powder
left behind when a mineral is crushed
or is rubbed against an unglazed
porcelain tile

25. Streak
 Use your ESRT page 16

26. Mineral Identification: Cleavage and
Fracture
 Cleavage and fracture describe how a
mineral breaks caused by the internal
arrangement of atoms
 Cleavage is a mineral breaking along
a flat plane
 Fracture is uneven and random
breaking

27. Breakage of Common
Minerals
 Use your ESRT page 16

28. Mineral Identification: Density
 Determining a mineral’s density
sometimes help determine what it is
 Recall: Density = mass/volume

29. Mineral Identification: Reaction with
Acid/Magnetic
 Some minerals bubble when acid is
dropped onto them
 Other minerals are magnetic

30. Other Distinguishing
Characteristics
 Use your ESRT page 16