The Study of Minerals

Question 1

What is a mineral?

Answer 1

A naturally occurring, inorganic solid with an orderly internal arrangement of atoms (called crystalline structure) and a definite, but not fixed, chemical composition.

Question 2

What are rock forming minerals?

Answer 2

The abundant minerals that often occur with each other in the rocks of Earths crust.

Question 3

Luster is a primary optical property which is the ability to transmit :

Answer 3

Light, color, and streak

Question 4

What are the primary physical properties of a mineral?

Answer 4

Luster, hardness, crystal form, cleavage or fracture, and specific gravity.

Question 5

What are the secondary (or “special”) properties of a mineral?

Answer 5

Magnetism, taste, feel, striations, tenacity, and the reaction with dilute hydrochloric acid.

Question 6

Define luster :

Answer 6

Luster descibes the manner in which light is reflected from the surface of a mineral.

Question 7

What is metallic luster?

Answer 7

Any mineral that shines with a metal-like appearance is said to have a metallic luster.

Question 8

What is nonmetallic luster?

Answer 8

Minerals that do not have a metallic luster, and may have one of a variety of lusters that include virteous (glassy), pearly, or earthy (dull, like soil or concrete) are said to have a nonmetallic luster.

Question 9

**The ability of a mineral to transmit light can be descibed as either : **

Answer 9

Opaque, translucent, or transparent

Question 10

**Define opaque : **

Answer 10

A mineral is opaque when no light is transmitted.

Question 11

Define translucent :

Answer 11

A mineral is translucent when light but not an image is transmitted.

Question 12

**Define transparent : **

Answer 12

**A mineral is transparent when an image is visible through the mineral. **

Question 13

Which physical property of minerals is the least reliable and why?

Answer 13

Color, because it can be manipulated by slight impurities.

Question 14

**Define streak : **

Answer 14

The streak of a mineral is the color of the fine powder of a mineral obtained by rubbing a corner across a piece of unglazed porcelain - called a streak plate.

Question 15

What is the most reliable property of a mineral?

Answer 15

Streak

Question 16

**Define hardness : **

Answer 16

Hardness is one of the most useful diagnostic properties of a mineral and is a measure of the resistance of a mineral to abrasion or scratching.

Question 17

**Define crystal form : **

Answer 17

Crystal form is the external appearance or shape of a mineral that results from the internal, orderly arrangement of atoms.

Question 18

Most _______ ________ consist of crystals.

Answer 18

inorganic substances

Question 19

**Crystal faces are the : **

Answer 19

Crystal faces are the flat external surfaces on a crystal.

Question 20

What are the sample minerals for the Mohs scale?

Answer 20

10. Diamond
11. Corundum
12. Topaz
13. Quartz
14. Orthoclase
15. Apatite
16. Fluorite
17. Calcite
18. Gypsum
19. Talc

Question 21

**Define cleavage : **

Answer 21

Cleavage is the tendency of some minerals to break along regular planes of weak bonding between atoms in the internal crystalline structure.

Question 22

What are cleavage planes?

Answer 22

Cleavage planes are smooth, flat surfaces produced when minerals that exhibit cleavage are broken.

Question 23

What are directions of cleavage?

Answer 23

Directions of cleavage are the number of different sets of planes that form the surfaces of a mineral crystal when it cleaves.

Question 24

How is cleavage determined?

Answer 24

Cleavage is determined by the band that holds atoms together, while crystal form results from the internal, orderly arrangement of the atoms.

Question 25

**Define fracture : **

Answer 25

**Fracture is when a mineral is broken and does not exhibit cleavage. **

Question 26

What are the three types of fracturing?

Answer 26

Irregular, splintery, or conchoidal (smooth curved surfaces resembling broken glass).

Question 27

**Define specific gravity : **

Answer 27

Specific gravity is a number that represents the ratio of the weight of a mineral to the weight of an equal volume of water.

Question 28

**Define magnetism : **

Answer 28

Magnetism is a characteristic of minerals, such as Magnetite, that have high iron content and are attracted by a magnet.

Question 29

**Define striations : **

Answer 29

Striations are closely spaced, fine lines on the crystal faces of some minerals.

Question 30

Define tenacity :

Answer 30

Tenacity is the manner in which a substance resists breaking.

Question 31

What are carbonate minerals?

Answer 31

Carbonate minerals are a group of minerals that release carbon dioxide when exposed to a drop of dilute hydrochloric acid.