Minerals and Mineral Families

What is a Mineral?

A substance found in the Earth that always has the same chemical composition

What is a Mineral?

I -

S -

O -

D -

A -

Inorganic

SolidOccurs naturallyDefinite chemical compositionAtoms in a pattern

Review

?? Is water a mineral? Why or why not?

No because it is a liquid

?? Is coal a mineral? Why or why not?

No because it is made from living things. (plants)

Only 8 elements make up 98.5% of the Earth.

• Oxygen• Silicon• Aluminum• Iron• Calcium• Sodium• Potassium• Magnesium

The 2 most common elements in the crust.

More than 90% contain Si and O

How do minerals form?

• Magma or lava cools and mineral compounds form.

How do minerals form?• Water containing dissolved ions slowly

evaporates

How do minerals form?• Existing minerals are changed by heat

and pressure

What do minerals look like?

• When atoms in a mineral line up in an orderly pattern a crystal forms.

• A crystal is a geometric solid with smooth sides or faces

Cubic Crystals

• All sides are equal length

• All sides meet at 90°

Orthorhombic Crystals

• All sides are unequal in length

• All sides meet at 90°

Tetragonal Crystals

• 2 sides are equal length

• 1 side is longer than others

• All sides meet at 90°

Hexagonal Crystals

• Six sided crystals• Sides meet at 60°

                                          

Monoclinic Crystals

• All sides are unequal in length

• Two sides meet at 90°

Triclinic Crystals

• All sides are unequal in length.

• No sides meet at 90°

Review

?? What determines which crystal shape will form?

The internal arrangement of the atoms

??Why are perfect crystals not commonly found in nature?

There is not enough room for them to grow

What kinds on minerals exist in Earth’s crust?

• Minerals can be divided in 7 groups or families

Family Name Common Elements

Examples

Silicates Oxygen and silicon

Quartz, feldspar

What kinds on minerals exist in Earth’s crust?

Family Name Common Elements

Examples

Carbonates Oxygen, carbon and a metal

Calcite, dolomite

What kinds on minerals exist in Earth’s crust?

Family Name Common Elements

Examples

Oxides Oxygen and a metal

Hematite, magnetite

What kinds on minerals exist in Earth’s crust?

Family Name Common Elements

Examples

Sulfides Sulfur and a metal

Pyrite

SULFATESCONTAIN

SULFUR AND OXYGEN

SO4

EXAMPLES

GYPSUM

HALIDESCONTAIN an ELEMENT

PLUS

Cl, Br, and F

NATIVE ELEMENTS

WHICH MINERAL FAMILY?

• FeCO3

• Mg2SiO3

• HgS

• Ag

• MgSiO3

• Al2O3

• Cu2CO3(OH)4

• KCl

PHYSICAL PROPERTIES

• HARDNESS – HOW EASILY IT CAN BE SCRATCHED

• LUSTER – HOW IT REFLECTS LIGHT

• COLOR – LEAST RELIABLE

• STREAK – COLOR OF ITS POWDER

• CLEAVAGE/FRACTURE

• FLORESCENCE, MAGNETISM, ODOR

Review

?? What is one way minerals can form?

Water containing dissolved ions slowly evaporates

Magma or lava cools and mineral compounds form

Existing minerals are changed by heat and pressure

Review

??What are the 2 most abundant minerals in the crust?

Oxygen and silicon

?? What family do they belong to?

Silicates

Review

?? What determines the shape of a mineral?

The internal arrangement of atoms

Review

??What are the 5 things that define a mineral?

Inorganic

Solid

Occurs naturally

Definite chemical composition

Atoms in a pattern

Review

?? How are minerals identified?

By their physical properties