Earth Space II - Intro to Mineralogy - Unit 6

1. Inorganic

2. Naturally occurring

3. Homogeneous solid

4. Definite chemical composition

5. Contains atoms that arrange in patterns to form a crystalline structure

What are the five requirements for a compound or element to be a mineral?

oxygen, silicon, aluminum

80% of all minerals contain at least 1 of 3 chemical elements: ______,_________,_______.

Crystal

_____ - solid form of a mineral having SMOOTH FLAT surfaces

Orthorhombic System

Which crystal shape/habit is this?

- Rhombus sided crystals usually with pointed ends

- Examples: sulfur, topaz

PYRITE

(iron sulfide)

FeS2

What is an example of a sulfide?

Sulfites

What is a mineral composed of a metal plus sulfur and oxygen?

silicon and oxygen plus any of the other minerals on the periodic table.

What are silicates composed of?

Graphite and diamond, both have the element carbon

What is an example of polymorphism?

Streak

The color of the powdered mineral on a piece of unglazed porcelain or tile

Streak

What property is only tested for metallic lusted minerals and dark nonmetallics?

2.2

What is the specific gravity value of halite?

7.5

What is the specific gravity value of galena?

Loadstone

(A variety of magnetite) is a natural magnet in the Earth's crust

Piezoelectric

Some minerals give off weak electrical charges such as Quartz

Optical projection

Image is transmitted by fibers to the top of the mineral surface

limestone and used to make cement

Where are carbonates found?

copper iron

What is Bornite composed of?

glassy

What is calcite's luster?

pearly

What is talc's luster?

silky

What is Gypsum's luster?

1

What is the hardness of talc?

hackly

- shows rough, jagged edges

(ex. copper)

sphalerite (ore of zinc), Chert & Flint (types of microcrystallized quarts)

What are examples of triboluminescent minerals?

Any CO3 mineral such as Calcite and Dolomite

What are example of minerals that fizz with the acid test?

40

How many common minerals are there?

Scratch

In the mohs scale of hardness, the mineral with the higher number can ________ any mineral beneath it or equal to it in hardness

Specific gravity

The relative weight of the mineral compared to the weight of an equal volume of water. (Similar to density, but no units are used.)

Fluorescent

Certain minerals glow different colors while under ultraviolet light

Phosphorescent

When the mineral continues to glow after the UV light is off it is __________.

4,000

How many minerals are recognized on the Earth?

15

Of the 40 common minerals, how many are true rock-forming minerals?

external and internal

A crystal shows an ______ and ______ pattern of its atoms

Rock Crystal Quartz

What is an example of a crystal?

crystalline

______ - mineral which just shows an internal pattern of its atoms (no external patter)

Crystalline, crystals

All minerals are ___________, but not all minerals are _______.

Mineraloids

______ - a solid or liquid substance that lacks an internal pattern of its atoms

Water, mercury, and opal

What are some examples of mineraloids?

1. Crystal shape

2. chemical composition

What are the scientific classifications of minerals?

Crystallography

_____ - the study of mineral crystals

Cubic (Isometric) system

Which crystal shape/habit is this?

- Cube-shaped crystals with 3 equal axies

- Examples: Halite, Pyrite, and Galena

Tetragonal System

Which crystal shape/habit is this?

- Four sided crystals with 1 unequal axis. Can have pyramids on top and bottom.

- Examples: Rutile, Zircon

Hexagonal System

Which crystal shape/habit is this?

- Six sided crystals (can have pointed ends)

- Examples: quartz, calcite

Monoclinic System

Which crystal shape/habit is this?

- Flat sheeted crystals

- Examples: Mica, Gypsum

Triclinic System

Which crystal shape/habit is this?

- The crystal is like the monoclinic in layers, but three different angles

- Examples: Microcline feblspar (Amazonstone)

Twinning

What is the special crystal shape?

staurolite, Gypsum, and Quartz

What are some examples of twinning?

Twinning

_____ - crystals grow together usually at right angles to each other

7

How many major chemical groups of minerals are there?

Native

"__________" elements - minerals composed of only 1 element on the periodic table

Gold, silver, copper, and sulfur

What are some examples of native elements?

Halides

_____ - smallest group of minerals composed of a metal plus a halogen (salt compound)

Halite (NaCl)

What is an example of a halide?

Oxides

____ - minerals composed of any metal plus the element oxygen

Hermatite (Iron oxide) a major ore of iron

What is an example of an oxide?

Sulfides

____ minerals composed of any metal plus the element sulfur

Carbonates

What is a mineral composed of any metal plus carbon and oxygen?

Silicates

What is the largest and most important group of minerals?

Into the light and dark silicates

How are silicates divided?

Quartz

What is the basic silicate?

quartz

What is the most common mineral on Earth?

Microcline Feldspar, KAlSi3O8

Most silicates are complex, like ___________

Polymorphism

____ - different minerals composed of same chemical elements, but having 2 different crystal structures

Mineralogists

_______ scientifically use the crystal shape and chemical composition, while amateurs use minerals' physical properties to identify them.

7

How many major physical properties are there?

Color

____ - probably the most noticeable feature of a mineral, but can fool the "best" in a positive identification

1. Different minerals may have the same color

2. Some minerals have impurities which give them different colors

3. Some minerals change color when weathered

What are the general rules of color in mineral identification?

Calcite and quartz

What is an example of different minerals having the same color?

Manganese gives amethyst quartz its purple color

What is an example of impurities giving minerals different colors?

Bornite

What is an example of a mineral changing color when weathered?

True

True or false? Certain minerals can be positively identified by their distinctive color

Azurite and malachite

What are examples of copper minerals (blue-green)

Luster

The way the light reflects or shines off a mineral

Metallic and nonmetallic

What are the two general types of luster?

Metallic

If the mineral looks like a metal, what luster group is it in?

Nonmetallic

If the mineral does not look like a metal

Pyrite and Galena

What are some examples of luster metallic minerals?

Quartz and calcite

What are some examples of nonmetallic luster minerals?

False

True or false? The color of the streak is the same as the color of the mineral

Hardness

The resistance of a mineral to being scratched

Friedrich Mohs

Who developed the mohs scale of hardness in 1822?

2.5

What is the hardness value of a fingernail?

3

What is the hardness value of a copper penny?

3.5

What is the hardness value of glass?

6.5

What is the hardness value of a steel washer?

Cleavage

the way a mineral tends to break into smooth, flat planes (usually splits along weaknesses in the internal or atomic structure of the mineral).

fracture

Unorganized breakage of a mineral. Uneven pattern with no smooth, flat surfaces

True

True or false? Perfect cleavage is rare with minerals. Most show fracture or a combination of cleavage/fracture

Conchoidal and hackly

What are some unique types of fracture of minerals?

2.6

What is the specific gravity value of quartz?

2.7

What is the specific gravity value of calcite?

3.2

What is the specific gravity value of fluorite?

4.1

What is the specific gravity value of sphalerite?

5 to 6

What is the specific gravity value of Pyrite?

19.3

What is the specific gravity value of gold?

True

True or false? Metallic minerals usually have higher specific gravity values

1. Making precise measurements with the balance to determine mass and with the graduated cylinder to determine volume.

2. May have impurities in the mineral sample which would affect SG value.

3. Some minerals may dissolve in water when tested.

What are the disadvantages of using the specific gravity test?

magnetic

What is certain minerals containing iron can be picked up by a magnet?

Tourmaline

The mineral _______ produces electrical charges when heated

Radioactivity

Some minerals such as uraninite and carnotite contain radioactive elements

Using Geiger counter

How can radioactivity be measured?