Introduction to Minerals

Question 1

Define Minerals

Answer 1

A naturally occurring, inorganic, solid, crystalline substance which has a fixed structure and a chemical composition which is either fixed or which may very within certain defined limits

Question 2

What are mineraloids

Answer 2

• amorphous solid materials without a fixed composition, i.e. they lack a crystal structure
• can be organic
• can be manmade

Question 3

Minerals are ________ solids.

Answer 3

crystalline

Question 4

Crystals are…

Answer 4

solids naturally bounded by flat faces meeting at sharp edges

Question 5

Crystal lattices are…

Answer 5

a crystal shape which reflects the regular arrangement of constituent atoms

Question 6

What 2 elements make up 75% of the earth’s crust

Answer 6

Oxygen and Silicon

Question 7

Most common mineral in earth’s crust

Answer 7

Silicate

Question 8

Minerals are made up of ______

Answer 8

bonded atoms

Question 9

What are the three main types of atomic bonding

Answer 9

• Ionic
• Covalent
• Metallic

Question 10

Ions are…

Answer 10

atoms with positive or negative charges due to loss or gain of electrons

Question 11

Anion

Answer 11

an atom that has gained electrons

• has a negative charge
• has more electrons than protons

Question 12

Cation

Answer 12

an atom that has lost electrons

• has a positive charge
• has less electrons than protons

Question 13

Ionic Bond

Answer 13

attraction of oppositely charged ions

Question 14

Covalent Bond

Answer 14

atoms share electrons

Question 15

what does ionic radius determine

Answer 15

How ions pack together to form minerals

Question 16

Coordination number

Answer 16

The number of anions around each cation in a crystal lattice and is controlled by ionic radii

Question 17

Radius ratio

Answer 17

radius of cation/radius of anion

Question 18

Coordination number and radius number relationship

Answer 18

coordination number increases with radius ratio

Question 19

The unit cell

Answer 19

the smallest arrangement of atoms which may be repeated regularly in three dimensions to form a crystal lattice

Question 20

How minerals grow

Answer 20

1) first a ‘seed’ forms
2) surrounding ions are attracted and attach to the surface
3) Mineral grows outwards from the centre
4) if space permits large well formed crystal will form

Question 21

Where do minerals grow in the earth

Answer 21

crust and lithosphere

Question 22

What are the mineral forming environments for igneous

Answer 22

• High temperature (>700degreesC), so melts
• Pressure and water content variable
• Minerals are able to form in free environment

Question 23

The igneous minerals that form in this environment are…

Answer 23

• moderately hard to hard
• anhydrous and hydrous
• good crystalline shape

Question 24

What are the mineral forming environments for metamorphic

Answer 24

• moderate to hight temperature (200 - 700 degreesC) so no melting
• low to high pressure
• abundant water in some cases (metasomatism)
• minerals form in a confined environment and their shape is strongl