2.1 Minerals Are All Around Us Minerals are basic building blocks of Earth.

2.1 Minerals Are All Around Us

Minerals are basic building blocks of Earth

Minerals are all around us.• Minerals are used all the time. • Copper in the wires that carry electricity to a device • Table salt, or halite (HAYL-YT), is a mineral • Minerals and rocks are not the same.– Minerals

• Formed in nature• Solid• Definite chemical makeup• Crystal structure • Always made up of the same materials in the same proportions

– Rocks• Formed in nature• Solid• Usually contains two or more types of minerals• Amounts of minerals may vary between the same types of rock

Minerals have four characteristics.

Is formed in nature

Is a solid

Has a definite chemical makeup

Has a crystal structure

Formed in Nature• Minerals are formed by natural processes• Every mineral can form without involvement by

living organisms• A few can be produced as part of an organisms

shells or bones.• Form in many ways– Halite (table salt) is formed when ocean water

evaporates – Granite develops when molten rock cools. – Talc (found in baby powder) is formed from the high

pressure and temperature deep in Earth.

Solid

• A mineral has a definite volume and a rigid shape• Liquids and gases are not minerals unless they

are in solid form– Examples• Liquid water is not a mineral, but ice is.• Copper is a mineral when in solid form, but melted copper

is a liquid, so it is not considered a mineral.

Definite Chemical Makeup

• Each mineral consists of a specific combination of atoms of certain elements.– Elements are substances that contain only one type of atom– Atoms are the smallest particle an element can be divided into

• Everything is made up of atoms.

• Some minerals (gold, copper) consist of one element of the same type

• Most minerals are compounds, substances consisting of several elements in specific proportions (NaCl)

• The types of atoms in a mineral help to make it unique• Atom bonds also help make it unique

Crystal Structure• Arrangements of atoms are characteristic of minerals• Crystals are solids in which the atoms are arranged in an

orderly, repeating, three-dimensional pattern• Each mineral has its own type of crystal structure• Two minerals can have the same chemical composition but

different crystal structures.– Diamond and graphite– Consist only of carbon– Arrangement of the carbon atoms result in different crystal

structures and properties. • Diamonds are extremely hard and have a brilliant sparkle.• Graphite is soft, gray, and dull.

• Perfect crystals rarely form in nature.– Needs to form in open space– Amount of growing space influences shape and size of crystals.

Minerals are grouped according tocomposition.

• Minerals are classified based on their chemical makeups• Out of thousands of minerals, only 30 are common in Earth’s crust• Called rock-forming minerals and make up most rocks in the crust.• Most common are silicates

– Contain oxygen and silicon (most common elements in crust) joined together

– Make up about 90 percent of the rocks in Earth’s crust– Most common rock-forming minerals are Quartz, Feldspar, Mica

• Carbonates– Contain carbon and oxygen joined together– Second most common group of rock-forming minerals

• Many other important mineral groups. – oxides contains the minerals from which most metals (tin, copper), are

refined.– Consists of an element, usually a metal, joined to oxygen (hematite)

Minerals are grouped according to composition.

Silicates are the most common rock-forming mineral group.

Carbonates are the second most common mineral group.

The oxides group contains the minerals from which most metals are refined

Minerals are grouped according to composition.

• Give three examples of silicates.• Quartz• Feldspar• Mica

• What are rock-forming minerals? List some examples.– Rock-forming minerals are a group of about 30

minerals that make up most of the rocks in Earth’s crust. Some examples are quartz, feldspar, mica, and calcite.