Matter and minerals

Question 1

Mineral

Answer 1

• Naturally occurring
• Solid within temperature range normally found at Earth’s Surface
• Orderly crystalline structure where atoms are arranged in an orderly, repetitive manner
• Well-defined chemical composition
• Generally inorganic, though some may contain carbon

Question 2

Valence electrons

Answer 2

Electrons in the outermost shell.

Question 3

Isotope

Answer 3

Atoms with differing proton and neutron counts.

Question 4

Ion

Answer 4

Atom with differing proton and electron counts, causing an electrical charge.

Question 5

Cation

Answer 5

Atom that with fewer electrons than protons and so has a positive charge.

Question 6

Anion

Answer 6

Atom with more electrons than protons and so has a negative charge.

Question 7

Compounds

Answer 7

Some combination of different elements

Question 8

Elements form chemical bonds in order to?

Answer 8

Fill their outermost shells with electrons

Question 9

Ionic bond

Answer 9

One element loses an electron and becomes positively charged. Another element gains an electron and becomes negatively charged. The oppositely charged ions are attracted and bond

Question 10

Covalent bond

Answer 10

electron orbits (shells) can overlap with those of adjacent elements and so electrons are shared.
e.g. Cl2 is the bond of two chlorine atoms sharing a single electron to fill their valence shell.

Question 11

Metallic bond

Answer 11

Metallic atoms pack together as cations. Their electrons are mobile and move about freely to be shared among the cations. Occurs among a small number of minerals e.g. copper.

Question 12

Diamond atomic structure

Answer 12

each carbon atom shares electrons with four adjacent carbon atoms in a tetrahedral arrangement.

Question 13

Different minerals have different crystal forms due to differences in?

Answer 13

The internal arrangement of atoms.

Question 14

What can we say about the faces and angles of a crystal?

Answer 14

Although some of the faces may grow larger than others, the angles between equivalent facer are constant for a given mineral.

Question 15

Polymorphs

Answer 15

two minerals that have the same chemical composition but differ in crystal structure. e.g. graphite/diamond, calcite/aragonite

Question 16

Silicates

Answer 16

Minerals comprised of silicon ions surround by four oxygen ions (SiO4)^-4. This is the basic building block is the Silicon-Oxygen Tetrahedron
General formula for silicates:
(SiO4)^-4 + cations.

Question 17

Pyroxene group

Answer 17

Two planes at right angles. Single chains of Silicon-Oxygen Tetrahedrons. e.g. augite

Question 18

Amphibole group

Answer 18

Two planes at 60 and 120 degrees. Double chains of silicon-oxygen tetrahedrons. e.g. hornblende

Question 19

Micas are examples of?

Answer 19

Sheet silicates

Question 20

Most common minerals in Earth’s crust?

Answer 20

Silicates

Question 21

Carbonates

Answer 21

Basic unit is the (CO3)^-2 complex. There are different carbonate minerals depending on which cation is attached to the carbonate complex. The two most important carbonates are calcite (CaCO3) and dolomite (CaMg(CO3)2)

Question 22

Oxides

Answer 22

Cations are bounded to oxygen: O^-2 + cations.
Two important oxides:
- Hematite (Fe2O3)
- Magnetite (Fe3O4)

Question 23

Sulfates

Answer 23

Sulfur is present as the sulfate ion (SO4)^-2
(SO4)^-2 + cations
Two important sulfates:
- Anhydrite (CaSO4)
- Gypsum (CaSO4 * 2H20)

Question 24

Sulfides

Answer 24

Many important ore deposits exist as sulfides:
S^-2 + cations
Two important sulfides:
- Pyrite (FeS2)
- Galena (PbS)

Question 25

Halides

Answer 25

Generally form ionic bonds.
Some precipitate from salty water.
Important Halides:
- Halite (NaCl)
- Sylvite (KCl)
- Fluorite (CaF2)

Question 26

Native Element Minerals

Answer 26

Composed of only one element

e.g. graphite (C), diamond (C), copper (Au), gold (Au), sulfur (S)

Question 27

Streak

Answer 27

the color left behind when scratching a mineral on a tile of unglazed porcelain.

Question 28

Hardness

Answer 28

the measure of the ease with which the surface of a mineral can be scratched.

Question 29

Tenacity

Answer 29

describes a mineral’s toughness, or resistance to breaking or deforming

Question 30

Cleavage

Answer 30

tendency of a crystal to break along flat planar surfaces.

• Covalent bonds are generally strong and have poor cleavage e.g. quartz
• Ionic bonds are relatively weak and yield good cleavage e.g. halite and calcite

Question 31

Fracture

Answer 31

tendency of a mineral to break along irregular surfaces other than cleavage planes.

• Conchoidal (smooth, curved surfaces)
• Fibrous (similar to splitting wood)
• Irregular

Question 32

Specific Gravity

Answer 32

a measure of the mass of a mineral divided by the mass of an equal volume of water.
Heavier minerals have higher specific gravity.

Question 33

Luster

Answer 33

the way a mineral reflects light
- Metallic (strong reflections by opaque minerals)
- Vitreous (reflects like glass)
- Dull (earthy)
- Greasy (appearance of being coated with oil)
Adamantine (brilliant luster of diamond)

Question 34

Form/Habit

Answer 34

the shape in which a crystal grows

• Bladed
• Prismatic
• Banded
• Botryoidal