INTRO: ROCKS & MINERALS

Question 1

Name two types of isotopes

Answer 1

Radioactive and Stable (Non-Radio Active)

Question 2

A stable configuration occurs when a valence shell contains…

Answer 2

Eight Electrons

Question 3

There are three main types of chemical bonds:

Answer 3

Ionic, Covalent, Metallic

Question 4

Ionic Bonds:

Answer 4

transfer electrons between atoms

Question 5

Covalent Bonds:

Answer 5

share electrons between atoms

Question 6

Metallic Bonds:

Answer 6

valence electrons move freely among atoms

Question 7

Diamond consists…

Answer 7

entirely of carbon atoms united by covalent bonds in a tetrahedral
structure with a repeating pattern of 8 atoms

Question 8

Crystal lattice:

Answer 8

The 3-D molecular structure of a mineral;

its configuration reflects relative sizes and
numbers of ions that make up the mineral

Question 9

To form a stable compound, the ions must have:

Answer 9

1) their ionic charges be in balance, and
2) right size to allow them to fit together

Question 10

Cation Substitution:

Answer 10

Cations of similar size and charges tend to substitute for one
another in the crystal lattice and can form compounds having the same crystal
structure but different chemical composition

Question 11

Definition of a mineral:

Answer 11

In geology, a mineral is a naturally occurring, inorganic solid, with a crystalline structure
and definite chemical composition formed by geological processes

Question 12

Characteristics of a Mineral:

Answer 12

1. naturally occurring
2. inorganic
3. solid
4. characteristic crystalline structure
5. definite chemical composition

Question 13

Crystalline solid

Answer 13

Minerals exhibit an ordered internal structure in which in which the atoms are
arranged in a regular, repeating pattern

Question 14

Chemical composition of a mineral and the way in which atoms are bonded
determines:

Answer 14

1. Mineral shape and appearance
2. Mineral hardness
3. The way in which a mineral breaks, also known as cleavage or fracture
4. The specific gravity or weight of a mineral
5. Optical properties such as color, luster, or diaphaneity

Question 15

There are three types of diaphaneity:

Answer 15

*Transparent minerals transmit light freely
*Translucent minerals transmit light although it maybe hard to see through them
*Opaque minerals do not transmit light at all and appear solid

Question 16

Three Main Types of Lustre:

Answer 16

1. Metallic luster: appearance of polished metal
2. Non-metallic luster: does not look like metal
3. Sub-metallic luster: somewhat metallic without a polished sheen

Question 17

Moh’s scale of hardness:

Answer 17

Relative scale of hardness
Softest (1) talc – hardest (10) diamond

Question 18

Cleavage is described by:

Answer 18

• Number of planes
• Angles between adjacent planes
• Constant for a particular mineral

Question 19

Fracture:

Answer 19

• Some minerals break unevenly (fracture) and do not exhibit cleavage
  – Smooth, curved surfaces when minerals break in a glass-like manner:
  conchoidal fracture
  – Others include fibrous and rough fracture (asbestos)

Question 20

Silicates

Answer 20

• Silicates are the most abundant group of minerals in the crust and mantle;
• They contain silicon bonded to an oxygen
  in a unit structure known as the
  silica tetrahedron;

– 4 oxygen atoms (-8) surround a much smaller silicon atom (+4)

• Most silicate minerals form at high temperatures

Question 21

How tetrahedra may be linked:

Answer 21

• independent tetrahedra (olivine, garnet)
• single chains (pyroxene group)
• double chains (amphibole group)
• Sheets (mica group)
• Framework (feldspars and quartz)

Question 22

Feldspar groups:

Answer 22

1. Alkali feldspars

(potassium or K-spar)
* Orthoclase, sanidine, microcline, anorthoclase

2. Plagioclase feldspars

(solid solutions between Na and Ca)
* Albite (Na) to Anorthite (Ca)

Question 23

Non-Silicates:

Answer 23

– Carbonates
– Sulfates
– Sulfides
– Halides
– Oxides
– Native elements

Question 24

Carbonate Minerals

Answer 24

Unlike silicates, most carbonates form at low temperatures near the Earth’s
surface – precipitated from solution in shallow seas or from groundwater

Prominent carbonate rocks include limestone and dolostone

Question 25

Sulfate Minerals

Answer 25

Formed at low temperatures near the earth’s surface mainly through
evaporation of groundwater, lake, or ocean waters

Question 26

Types of Sulfate Minerals:

Answer 26

Gypsum is a common sulfate mineral:
– Does not react with HCl
– Hardness of 2 (Moh’s Scale) easily scratched with fingernail

Alabaster:
fine-grained, massive gypsum

Plaster of Paris:
powdered form of calcium sulfate. When
water is added it forms a gypsum cement

Sulfide minerals are major ores of lead, zinc, copper, and molybdenum

Question 27

Iron Oxides

Answer 27

Iron oxides form a small percentage of rocks

They are important ore bodies:

– magnetite (black streak and magnetic)
– hematite (rusty streak and not magnetic)

Question 28

Halide Minerals

Answer 28

Halides have anions of the halogen elements (fluorine, chlorine, bromine, iodine).
– Halides are made of ionic bonds
– Form as mineral-rich waters evaporated
– Halite (sodium chloride - NaCl) is salt
– Sylvite (potassium chloride - KCl) is a potassium salt (potash)

Question 29

Native Elements

Answer 29

• Minerals of a single element
  – Gold, Silver, Copper, Sulphur

Question 30

Rock:

Answer 30

Consolidated solid material comprised of aggregates of one or more
minerals or solidified organic material.

Most rocks consist of more than one mineral, for example granite = quartz,
feldspar, mica, and hornblende.

Some rocks are composed of only one mineral, for example limestone formed
from coral reefs (calcite).

Question 31

Three
fundamental rock types that reflect their origin and processes of formation:

Answer 31

1. Igneous,
2. Sedimentary
3. Metamorphic

Question 32

Igneous rocks:

Answer 32

are derived from the cooling and crystallization of molten rock

Question 33

Intrusive (Plutonic)

Answer 33

magma emplaced at depth

Question 34

Extrusive (Volcanic)

Answer 34

lava extruded at surface

Question 35

Sedimentary rocks:

Answer 35

are formed from the weathered remnants of pre-existing
rock (sediment) that has been compacted or cemented (i.e., process of
lithification)
or from minerals precipitated from water by chemical or biological
processes

Question 36

Metamorphic rocks:

Answer 36

are formed by the transformation of pre-existing rock by:

• high temperature,
• high pressure, and
• chemically active fluids.