Chapter 3 & 4
Section 1: What Is A Mineral?
Is It A Mineral? It might be, if you can answer yes to the following questions: Is it a solid? Is it formed in nature? Is it nonliving material? Does it have a crystalline
structure?
A mineral is a naturally formed, inorganic solid with a crystalline structure.
http://www.flickr.com/photos/mheisel/2936798136/
Minerals can’t be gases or liquids!
No Air & No
Water
Crystalline materials made by people aren’t classified as minerals.
No Man Made Gemstones &
No Tires
A mineral is inorganic, meaning it isn’t made of living things. No Teeth & No
Bones
Minerals are crystals, which have a repeating inner structure that is often reflected in the shape of the crystal. Minerals generally have the same chemical composition throughout.
www.rblewis.net/.../WebQuests/atoms/atoms.jpg
Lets break it down: Minerals are made up
of Elements Elements are pure
substances that can’t be broken down into simpler substances
Atoms are the smallest part of an element
More than one type of atom stuck together is a compound
Most minerals are made up of compounds of different atoms
Halitez.about.com/d/chemistry/1/0/Y/6/halite.jpg
When atoms are held in a set structure it is called a crystal (or a crystalline structure)
http://www.flickr.com/photos/alishav/3221701134/
SILICATE
Minerals that contain Silicon and Oxygen
90% of Earth’s crust is made up of Silicate Minerals
Examples: Feldspar, Biotite Mica & Quartz
NONSILICATE
Minerals that do not contain Silicon & Oxygen
Examples: Native copper, Gold, Diamond, Calcite, Fluorite and Galena.
mrbarlow.files.wordpress.com/2009/02/diamond.jpg
Section 2: Identifying Minerals
Now that you know your sample is a mineral… we need to learn how to identify what mineral it is
Properties to ID Minerals Color Luster Streak Cleaving & Fracture Hardness Density Special Properties
Not a good indicator for IDExample: Pyrite (Fool’s Gold) has a
golden color normally – but when exposed to weather for a long time it turns black
www.3dchem.com/imagesofmolecules/pyrite2.jpg
Luster is the way a surface reflects light
Example: Dull or ShinyTypes of Luster:
Metallic/Glassy (Shiny) Submetallic (Dull) Nonmetallic (Dull)
www.thunderhealing.org/rock/anglesite.jpg
Streak is the color of a mineral’s powdered form
More reliable than Color because weathering doesn’t change the Streak Color
geology.csupomona.edu/alert/mineral/streak.jpg
Minerals break in certain ways depending on how the atoms are arranged Cleaving: When minerals break along
flat surfaces▪ Ex. Diamonds and Rubies
Fracture: When minerals break unevenly or irregularly▪ Ex. Quartz
Hardness refers to a mineral’s resistance to being scratched Example: Diamond is
the hardest mineral Moh’s Hardness Scale:
▪ Scale 1 – 10 Reference Minerals – p. 66
z.about.com/.../1/0/W/A/1/magnetitemassive.jpg
Density is how much matter there is in a given amount of space
Density of Water: 1 g/cm3
Specific Gravity = Object’s Density/Density of Water
The specific gravity of an unknown mineral can tell you it’s identity
Some minerals have unique properties: Taste (ex. Halite) Fluorescence (ex. Calcite & Fluorite) Chemical Reaction (ex. Calcite) Optical Properties (ex. Calcite) Radioactivity (ex. Radium & Uranium can
be detected in a mineral) Magnetism (ex. Magnetite & Pyrrhotite)
Section 3: The Formation & Mining of Minerals
Where a mineral is formed determines its properties
Minerals can form in many places Deep Below the Earth’s
surface, or at or near the Earth’s surface
http://www.flickr.com/photos/wolfgangstaudt/2241232829/
Minerals can form in: Evaporating Saltwater Limestones Metamorphic Rocks Hot-water Solutions Pegmatites Plutons
See pg. 68 – 69 in your text book and answer the following questions and put the answers on your note sheet!
This picture shows a mineral deposit at a geyser. Which of the 6 situations on page 68 and 69 explain its formation?
http://www.flickr.com/photos/jurek_durczak/312736434/
Name 3 minerals that are formed from magma.
http://www.flickr.com/photos/hurtubia/375483426/
How To Mine Minerals Two Possibilities:
Surface Mining▪ Ex. Open pits or quarries▪ Ex. Copper Ore &
Aluminum rich minerals Deep Mining
▪ Ex. Diamonds & Coal
Effects of Mining Minerals ores are turned
into common metals, as seen on pg. 71
Harmful Effects Destroys habit Waste gets into water Reclamation: turning the
mining land back into its original state after mining, required on public land, expensive & time consuming