Chapter One: Building Blocks of Rocks
Minerals vs Rocks
A. Mineral definition
Naturally occurring
Inorganic
Solid
Have a definite chemical structure
B. Nearly 4000 known minerals
C. Rocks are aggregates ( mixtures) of minerals
Composition and structure of minerals
Elements
Basic building blocks of minerals
Over 100 known
Atoms
Smallest particles of matter
Have all the characteristics of an element
How atoms are constructed
Nucleus, which contains
Protons - positive electrical charges
Neutrons - neutral electrical charges
Energy levels, or shells
Surround nucleus
Contain electrons - negative electrical charges
Atomic number is the number of protons in an atom's nucleus
Bonding of atoms
forms a compound with two or more elements
Ions are atoms that gain or lose electrons
Isotopes
Have varying number of neutrons
Have different mass numbers - the sum of the neutrons plus protons
Many isotopes are radioactive and emit energy and particles
Minerals
Properties of minerals
Crystal form
Luster
Color
Streak
Hardness
Cleavage
Fracture
Specific gravity
Other
Taste
Smell
Elasticity
Malleability
Feel
Magnetism
Double refraction
Reaction to hydrochloric
A few dozen minerals are called the rock - forming minerals
The eight elements that compose most rock - forming minerals are oxygen ( O ), silicon ( Si ),
Aluminum ( Al ), iron ( Fe), calcium ( Ca ), sodium ( Na ), potassium ( K ), and magnesium ( Mg )
Most abundant atoms in Earth's crust are
.Oxygen ( 46.6 percent by weight )
.Silicon ( 27.7 percent by weight )
Mineral groups
Silicate minerals
Most common mineral group
Contain silicon - oxygen tetrahedron
Groups based upon tetrahedron arrangement
Olivine - independent tetrahedron
Pyroxene group - tetrahedron are arranged in chains
Amphibole group - tetrahedron are arranged in double chains
Micas
Tetrahedron are arranged in sheets
Two types of mica
Biotite ( dark ) and
Muscovite ( light )
Feldspar
Feldspars
Three - dimensional network of tetrahedrona.
b. Two types of feldspars
1. Orthoclase and
2. Plagioclase
Quartz - three dimensional network of tetrahedron
Feldspars are the most plentiful mineral group
Crystallize from molten material
Nonsilicate minerals
A. Major groups
1. Oxides
2. Sulfides
3. Sulfates
4. Halides
5. Carbonates
6. " Natives " elements
B. Carbonates
1. A major rock - forming group
2. Found in the rocks limestone and marble
C. Halite and gypsum are found in sedimentary rocks
D. Many have economic value
Minerals resources
1. Reserves are already identified deposits
2. Ores are useful metallic minerals that can be mined at a profit
3. Economic factors may change and influence a resource