Minerals P.2

Question 1

Crystal shape aka

definition

Answer 1

Habit: shape of ind. crystals or aggregates of crystals

Question 2

Habit of quartz

Answer 2

six sided (hexagon) and pyramid-like ends

Question 3

Habit of garnet, magnetite, pyrite

Answer 3

12-sided, octahedron, blocky

Question 4

What minerals have a cube-like habit?

Answer 4

fluorite and halite

Question 5

Habit adjectives

Answer 5

blocky, banded, cubic, fibrous, bladed (elongated), tabular (tablet shaped), granular (aggregates of crystals)

Question 6

Hardness
what scale is used? tools associated with it and their hardness

Answer 6

resistance to being scratched
mohs scale

fingernail (2.5)
penny (3.5)
iron nail (4.5)
glass plate (5.5)
streak plate (6.5)

Question 7

Hardness (what will be scratched, who is the scratcher?)

Answer 7

scratched: softer mineral
scratcher: harder mineral

Question 8

what is the chemical formula for graphite? hardness compared to diamond

Answer 8

C, softer bc the diamond has a more compact crystal structure

Question 9

what are hard minerals used as

Answer 9

abrasives

Question 10

Index minerals in order from soft to hard

Answer 10

talc, gypsum, calcite, fluorite, apatite, orthoclase, quartz, topaz, conundrum, diamond

Question 11

what determines hardness (3)

Answer 11

• repeating pattern
• strength and type of bond
• crystalline structure

Question 12

abrasives using minerals

Answer 12

saw: diamonds
sandpaper: garnet

Question 13

what do people use to color their skin and hair? another mineral with distinctive color

Answer 13

hematite (red) and limonite, a variety of goethite, (yellow)

malachite (green/bluish)

Question 14

cleavage

Answer 14

tendency of a mineral to break along planes on weak bonding (easier to break in that direction)

Question 15

cleavage planes vs directions of cleavage

Answer 15

planes: smooth, flat surfaces
directions: cleavage suface with a different orientation

Question 16

how do you know when a mineral demonstrates cleavage? how do you find cleavage planes?

Answer 16

when broken, pieces will all have the same geometry
rotate it in light

Question 17

what group of minerals have 1 direction of cleavage, what’s special about them? what two minerals are a part of that group? analogy

Answer 17

Micas (flat sheets that can peel)
includes muscovite (lighter) and biotite (darker)
book pages can be peeled, but you can’t bend the book spine

Question 18

how many directions of cleavage does halite have? Angles? habit

Answer 18

3 directions, 90 degrees, cubic

Question 19

how many directions of cleavage does quartz have?

Answer 19

none, fractures into pieces that don’t resemble each other or the original crystal bc Si&O bonds are equally strong

Question 20

how many directions of cleavage does olivine have?

Answer 20

none, fractures into pieces that don’t resemble each other or the original crystal

Question 21

how many directions of cleavage does feldspar have? angles?

Answer 21

2 directions, 90 degrees

Question 22

how many directions of cleavage does hornblende have? angles

Answer 22

2 directions, 120 degrees and 60 degrees

Question 23

how many directions of cleavage does calcite have? angles? shape

Answer 23

3 directions, 75 degrees, rhombus

Question 24

how many directions of cleavage does fluorite have? galena?

Answer 24

4 directions
3 directions

Question 25

Fracture

Answer 25

minerals that don't have cleavage (chem.bonds are equally strong in all directions)

Question 26

types of fractures

Answer 26

irregular: uneven surfaces conchoidal: smooth, scoop curved surfaces with dangerous edges before fracture

Question 27

ex of minerals w/conchoidal fracture

Answer 27

quartz olivine

Question 28

tenacity adjectives

Answer 28

resistance to breaking, bending, deformation brittle, malleable, sectile, elastic

Question 29

minerals that are brittle 2 ex

Answer 29

minerals that are ionically bonded fluorite and halite

Question 30

minerals that are sectile 2 ex

Answer 30

minerals that can be cut into thin shavings gypsum and talc

Question 31

minerals that are elastic

Answer 31

micas

Question 32

specific gravity definition heavier =

Answer 32

ratio of a mineral's weight to an equal volume of water higher specific gravity

Question 33

other properties: talc calcite garnet (what does it look like)

Answer 33

soapy reaction to dilute hydrochloric acid (fizzes and produce CO2) & double refraction (letters appear twice) glassy gemstone

Question 34

how many directions of cleavage does garnet have?

Answer 34

none