Lecture 1// Minerals

Question 1

Rock

Answer 1

Aggregate of one or more minerals.

Question 2

Mineral

Answer 2

1) a naturally occurring, inorganic solid with a definite chemical composition (or narrow range), and has an orderly atomic structure.

Identified by 7 physical properties (also called as diagnostic properties).

Question 3

1) Cleavage

Answer 3

Breakage along planes of weakness

Examine sample for planer breakage surface in one or more specific directions.

Question 4

2) Fracture

Answer 4

Breakage, not along cleavage plane

Examine sample for either irregular or conchoidal breakage surfaces.

Question 5

3) Hardness

Answer 5

Resistance to scratching or abrasion

Use materials of known hardness to determine hardness of sample (Mohs Hardness Scale)

Question 6

4) Lustre

Answer 6

Character of reflected light

Does sample appear metallic/sub-metallic or non-metallic?

Question 7

5) Crystal Form

Answer 7

Geometric shape formed by the growth of crystal faces

Describe geometric shape: cubic, hexagonal, etc. Not commonly seen in most samples. Be careful to distinguish the faces of crystals from cleavage planes.

Question 8

6) Reaction to HCl

Answer 8

Chemical interaction of weak hydrochloric acid (HCl) and calcium carbonate (CaCO3)

Place a drop of HCl on sample and watch for a reaction (bubbles).

Question 9

7) Streak

Answer 9

Colour of the mineral when the crystal is powdered

Rub Sample on porcelain to determine colour of streak.

Question 10

Massive

Answer 10

Mineral grains that are cramped for space becomes “Intergrown,” and are said to be m a s s i v e

Question 11

Mohs Hardness Scale

Answer 11

1 Talc
2 Gypsum
2.5 Fingernail
3 Calcite
3.5 Copper penny
4 Flourite
4.5 Wirenail
5 Apatite
5.5 Glass & knife blade
6 Orthoclase
6.5 Streak plate
7 Quartz
8 Topaz
9 Corundum
10 Diamond