Minerals

What is a mineral?

definition: an element or chemical compound that is normally crystalline and is formed as a result of geologic processes

ALL MINERALSshare 5 common

traits!

How can you remember them?

COINS!

ALL MINERALS- COINS!Organized

Very specific pattern/arrang

ement of atoms. Inorganic

Not formed of animal or plant

material.

CrystallineHaving a specific internal structure, made of 1 or more

elements.

NaturalNot man-

made.

SolidNot liquids or

gases.

Minerals can be made up of

individual elements or compounds.

Au

Gold

NaCl

Halite

native mineral: mineral made up of single elements

ex. copper, silver, diamond, sulfur

How do minerals form?

•from molten Earth materials•evaporation of water•heat and pressure

•Although over 4,000 different kinds of minerals exist, only a few dozen are considered common

Mineral Identification

•Hardness•Streak•Cleavage•Luster•Color

Hardness- a mineral’s resistance to scratching

* See Moh’s Scale of Hardness in your lab guide

Streak

- color of a mineral’s powder

Cleavage

-the tendency of some minerals to break along distinct planes-*if a mineral has cleavage, when it is struck, every fragment will have the same shape

Luster- the way a mineral shines in reflected light

- either metallic or nonmetallic (for our lab)

Color- most noticeable yet least useful

Why?- slight impurities can make clear minerals colored.... ex. diamonds

Some other additional tests:

• Fracture – this occurs when the minerals breaks at random spots (not cleavage)

• Specific gravity – ratio of a substance’s weight to the weight of an equal volume of water

There are also special tests used to identify specific minerals

Effervescence - ex. acid test calcite will fizz when hydrochloric acid (HCl) is placed on it.

Magnetism – magnetite is magnetic!

Gemstones – a form of mineral that can be

polished for monetary value

Quartz – when it contains small amounts of iron we call it amethyst

Corundum – is used in emery boards and sand paper; when it contains minor impurities and is polished it is sold as ruby and sapphire

•

Cubic zirconia

• This is a synthetic (man-made) diamond

• It is a durable stone, but not as hard as a real diamond

• Is it a mineral?