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Minerals
Building blocks of rocks and our
Earth.
Chapter 29 section 3
What is A Mineral?
 Mineral
- a solid, naturally-occurring,
inorganic element or compound with
defined chemical composition. They
are also crystalline in structure. Based
on regular arrangement of atoms or
ions within it.
Rock forming minerals
very common on Earth’s surface
 The 20 most common make up 95% of
Earth’s crust
 Quartz, and orthoclase feldspar are the
most common
 Silicate minerals – minerals containing
atoms of silicon (Si) and oxygen (O).
 Nonsilicate – minerals that do not contain
Si. There are 6 groups.

Crystalline Structure
– natural solid with definite
internal pattern.
 Large crystals show internal
structure
 If crystal forms in UNRESTRICTED
environment a single large crystal
WILL develop.
 Crystal
Identifying Minerals

Characteristics of Minerals – minerals are
identified by their properties.
 Color- the color of it. Color is unreliable
 Luster- the way light is reflected from
fresh surface of the mineral
 Metallic: looks like polished metal.
 Nonmetallic: glasslike, waxy, pearly,
brilliant (diamond), dull or earthy, and
many more.
Identifying Minerals
Streak- color obtained when mineral is
rubbed across the surface of an unglazed
porcelain tile.
 Streak is more important than color
mineral true color.
 Cleavage - tendency of mineral to split on
flat surfaces.
 Fracture – tendency of mineral to break
unevenly

Identifying Minerals
 Hardness
- Resistance of a mineral to
scratching
 Moh’s Scale of Mineral Hardness.
 19th century German mineralogist,
Friedrich Moh.
 Know the chart on page 578.
Identifying Minerals

. Common materials to estimate hardness
 fingernail-hardness about
2.5
 copper penny-hardness
3 to 3.5
 steel nail-hardness
5 to 5.6
 window glass-hardness
5.5 to 6
Rocks
Types of Rocks
Igneous Rocks
Metamorphic Rocks
Sedimentary Rocks
Types of Igneous
Rocks
Intrusive: Formed underground by trapped,
cooled magma, large mineral crystals
 Extrusive: Formed above ground when
volcanoes erupt and magma cools, smaller
mineral crystals.

Examples of Igneous Rocks
Intrusive Igneous
Extrusive Igneous
Granite
Scoria
Diorite
Obsidian
Sedimentary Rocks
How They are Made

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Wind and water break down the earth
Bits of earth settle in lakes and rivers
Layers are formed and build up
Pressure and time turn the layers to rock
Sedimentary Rock Classification
– composed of fragments (clasts) of
pre-existing rock transported some distance
from their points of origin
 Chemical – form when standing/trickling
water evaporates, leaving dissolved
minerals behind.
 Organic – an accumulation of sedimentary
debris caused by organic processes. Plants
and animals.
 Clastic
Types of Sedimentary Rocks
Sandstone Clastic
Gypsum Chemical
Limestone Organic
Conglomerate Clastic
Shale Clastic
Metamorphic Rocks
Rocks that have changed
 They were once igneous or
sedimentary
 Pressure and heat changed the
rocks
 2 types: Regional and Contact
 Contact occurs near magma
chambers
 Regional occurs where
continents collide

Types of Metamorphic Rocks
Marble
Gneiss
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