Minerals

Question 1

Properties of minerals

Answer 1

Color
Streak
Luster
Hardness
Density 
Cleavage
Fracture

Question 2

Five Characteristics of Minerals

Answer 2

1. Definite chemical composition
2. Definite crystal structure
3. Inorganic
4. Solid
5. Naturally formed/occurring

Question 3

Definite chemical composition

Answer 3

The elements and the amounts of them present never change for a specific type of mineral.

Question 4

Definite crystal structure

Answer 4

Faces and edges; the unique arrangements of atoms and molecules.

Question 5

Inorganic

Answer 5

Not made of a living (or once living) thing.

Question 6

Solid

Answer 6

Doesn’t take the shape of its container.

Question 7

Naturally formed

Answer 7

Not man-made; made by the earth naturally. Minerals are found around the world in many of the same places on earth.

Question 8

Color

Answer 8

Many minerals are distinctly colored but have a variety of hues. Color should never be the only test for identifying minerals.

Question 9

Streak

Answer 9

The color a mineral displays in finely powdered form. It may be completely different from the color of the mineral itself. It is the left-behind residue when you rub the mineral across a piece of unglazed porcelain (streak plate).

Question 10

Luster

Answer 10

The way a mineral’s surface reflects light. Two types: metallic=shiny like a metal; nonmetallic=not metallic.
Nonmetallic
1. Glassy (quartz)
2. Pearly (talc)
3. Greasy (graphite)
4. Silky (gypsum; matte and soft)
5. Resinous (sulfur; dirty/earthy)
6. Adamantine (diamond; color variations in diamonds)

Question 11

Hardness

Answer 11

Moh’s Hardness Scale (1-10)
Talc=lowest/softest; diamond=highest/hardest
Hardness=ability to be scratched 
Minerals above can scratch minerals below; minerals below can’t scratch minerals above.
2.5: fingernail
3.5: penny
5.5: knife/glass plate
6.5: steel nail
8.5: drill bit

Question 12

Hardness continued

Answer 12

This is one of the most reliable ways to identify minerals. It compares the resistance of a mineral to being scratched by 10 reference minerals. Essentially, it is a scratch test.
Extra: it was named after Friedrich Mohs, a German mineralogist. It was developed in 1812.

Question 13

Density

Answer 13

Specific gravity; defined as amount of matter per unit volume. Density = mass/volume. Specific gravity is describing gravity in minerals.

Question 14

Cleavage

Answer 14

The line within the mineral that is the breaking point. It is the way some minerals break along certain lines of weaknesses in structure. Basically lines of weaknesses.

Question 15

Fracture

Answer 15

Description of the way a mineral tends to break.

1. Conchoidial- smooth curve
2. Hackly- sharp, jagged edges
3. Uneven- rough and irregular
4. Fibrous- shows fibers