Transcript Minerals - Madison Public Schools

Minerals
Chapter 3
Sec. 1 & 2
What Is a Mineral?
• A mineral is a naturally formed,
inorganic solid that has a definite
crystalline structure.
• All minerals contain one or more of
the 92 naturally occurring elements.
What is a Mineral?
• Answer four questions.
• If any answer is “no” – NOT a
mineral!
What is a Mineral?
• 1) Is it nonliving material?
• 2) Is it a solid?
• 3) Is it formed in nature?
• 4) Does it have a crystalline
structure?
What Are Crystals?
• Crystals are solid, geometric forms of
minerals
• Repeating pattern of atoms or molecules
creates the crystals
• A crystal’s shape is determined by the
arrangement of the atoms or molecules
within the crystal.
Crystal Structures
Two Groups of Minerals
Silicate vs. Nonsilicate
• Silicate Minerals: Minerals that
contain a combination of silicon and
oxygen molecules. These minerals
make up more than 90% of Earth’s
crust. Examples: Quartz, Feldspar,
and Mica.
• Nonsilicate Minerals: Minerals that
do not contain a combination of the
elements silicon and oxygen. They
are made up of carbon, oxygen
(without silicon), fluorine, and sulfur.
Examples; Copper, Calcite, Fluorite,
and Gypsum
Identifying Minerals
• There are seven ways to
determine the identity of
minerals.
Color
• Not usually the best way to identify a
mineral; for reasons such as
impurities.
Luster
• The way a surface reflects light;
usually described as shiny or dull
• Shiny = metallic luster
• Dull = submetallic, nonmetallic
• Observe samples
Streak
• The color of a mineral in powdered
form.
• A mineral’s streak can be found
rubbing the mineral against a piece
of unglazed porcelain called a streak
plate.
Cleavage and Fracture
• Cleavage: the tendency of some
minerals to break along smooth, flat
surfaces.
• Fracture: the tendency of some
minerals to break unevenly along
curved or irregular surfaces.
This sample of quartz shows a curved fracture pattern called conchoidal fracture.
Hardness
• A mineral’s resistance to being scratched.
• Scientists use Mohs hardness scale to
determine the hardness of minerals.
• ***The greater a mineral’s resistance to
being scratched is, the higher the
mineral’s rating is.
Moh's Hardness Scale
Density
• The measure of how much matter is
in a given amount of space.
Special Properties
• Some minerals can be identified by
special properties they have, such as
taste (NEVER taste in science class!),
magnetism, fluorescence,
radioactivity, chemical reaction, and
optical properties.
Special Properties
What are Rocks?
• Rocks are a combination of one or more
minerals.