Minerals

Chapter 9.1

Minerals1)Minerals

a)A mineral is a natural inorganic, crystalline solid found in the Earth’s crust.

i)An inorganic substance is one that is not made up of living things or the remains of living things.

ii)Every mineral is unique and can be made up of a single element such as copper or a compound of elements such as pyrite.

What is a Mineral?2) What is a Mineral?

a)There are four main questions to answer when identifying if a substance is a mineral or not.i)Is a substance inorganic?

(1)Coal is organic and not a mineral.ii)Does the substance occur naturally?

(1)Silver occurs naturally while steel does not.

What is a Mineral?i) Is the substance a solid in crystalline form?

(1)Natural gas is not a solid.ii) Does the substance have a definite chemical

composition?(1) Halite is made of sodium and chlorine and has

a specific crystalline pattern. While concrete is made up of several substances, the amounts of the substances changes depending on the use of the concrete.

Kinds of Minerals3) Kinds of Minerals

a)Over 3,000 minerals have been identified, but fewer than 20 are common. i)Out of the 20 common minerals, 10 of

them make up 90% of the mass of the Earth’s crust.

Kinds of Mineralsb) All minerals can be classified into two main

groups: silicate and non-silicate minerals. i) Silicate minerals contain atoms of silicon and

oxygen. ii)While quartz only consists of silicon and oxygen,

most silicate minerals also contain one or more other elements.

iii)Silicate minerals make up 96% of the Earth’s crust and 50% of the Earth’s crust is made up of feldspar minerals.

Kinds of Mineralsc) Non-silicate minerals do not contain silicon.

i) Only 4% of the Earth’s crust is made up of nonsilicate minerals.

ii)Nonsilicate minerals are classified into six major groups.

(1)Carbonates(2)Halides(3)Native elements(4)Oxides(5)Sulfates(6)Sulfides

Crystalline Structure4) Crystalline Structure

a)All minerals in the Earth’s crust have a crystalline structure.

b)Crystalline structures are characterized by a specific geometric arrangement of atoms or ions.

Crystalline Structurec) A crystal is a natural solid with a definite

internal patter. d)Most of the time this crystalline structure is can

only be seen under a microscope. However, some crystalline structures can easily be seen such as calcite, quartz, and halite.

e)There are six crystalline shapes that can form and help identify minerals.

Crystalline Structure5) Crystalline Structure and

Silicatesa)While there are many silicate

minerals, they are all made up of the same basic building blocks.

Crystalline Structurei)This basic building block consists of four

oxygen atoms arranged in a pyramid with one silicon atom in the center.

ii)This structure is known as the silicon-oxygen tetrahedron.

iii)This tetrahedron combines in many different arrangements to produce the many silicate minerals.

Tetrahedral Arrangements6) Types of Tetrahedral Arrangements

a)The isolated tetrahedral silicates contain tetrahedrons that are linked by atoms other than silicon and oxygen.

b)Ring silicates for when the tetrahedral are joined into three, four, or six-sided rings by oxygen atoms.

Tetrahedral Arrangementsc) In a single-chain silicate, each tetrahedron is

bonded to two others by shared oxygen atoms.d)In double-chain silicates, two single chains of

tetrahedral bond to each other. e)In sheet silicates, each tetrahedron shares three

oxygen atoms with other tetrahedra and the fourth oxygen atom is bonded with potassium or aluminum which joins one sheet to another.

Tetrahedral Arrangementsf) In a framework silicate, each tetrahedron

is bonded to four neighboring tetrahedra. i)The mineral quartz is formed by only silicon-

oxygen tetrahedrons. However, other minerals can be formed by replacing the silicon atom of the tetrahedron with another element such as aluminum. This creates the feldspars.