1. Chapter 2: Matter and Minerals
Section 2.6 Mineral Groups

2. Mineral Groups However, no more than a few dozen are abundant
There are over 4,000 minerals that have been named
However, no more than a few dozen are abundant
They make up most of the rocks of Earth’s crust
They are referred to as rock-forming minerals

3. Mineral Groups
Although less abundant, many other minerals are used extensively in the manufacture of products that are called economic minerals
Economic minerals and rock-forming minerals are not mutually exclusive
When found in large deposits, some rock-forming minerals are economically significant
Example: calcite mineral which is found in sedimentary rock and also has many uses including the production of cement

4. Mineral Groups Elements in order of abundance from most to least:
Only 8 elements make up the vast majority of the rock-forming minerals and represent more than 98% (by weight) of the continental crust
Elements in order of abundance from most to least:
Oxygen
Silicon
Aluminum
Iron
Calcium
Sodium
Potassium
Magnesium

6. Mineral Groups
Silicon and oxygen are by far the most common elements in Earth’s crust
These two combine to form the basic “building blocks” for the most common minerals know as silicates
Silicates account for more than 90% of Earth’s crust
Over 800 silicate minerals are known

7. Mineral Groups
The other, less abundant minerals are referred to as the nonsilicates
Some are very important economically
Some common nonsilicates include:
Carbonates
Sulfates
Halides
They provide us with:
Iron & aluminum to build automobiles
Gypsum for plaster and drywall
Copper wire that carries electricity and connects us to the Internet

8. Silicate Minerals
Silicate minerals contain: oxygen & silicon atoms
Most contain one or more additional elements in their crystalline structure
Those elements give rise to the varied silicate minerals and their different properties
All Silicates have the same fundamental building block called the silicon- oxygen tetrahedron
Consists of 4 oxygen atoms surrounding a smaller silicon atom
The structure determines the type of cleavage that forms with each mineral
2 most common silicate minerals include: Feldspar and Quartz

9. How Silicate Minerals Form
Most silicates crystallize from molten rock as it cools
Cooling can occur at or near the Earth’s surface (low temperature and pressure) OR
At great depths (high temperature and pressure)
The environment during crystallization and the chemical composition of the molten rock mainly determine which minerals are produced
Examples:
Olivine crystallizes at high temperatures (2200 F)
Quartz crystallizes at low temperatures (1300 F)

11. Nonsilicate Minerals
Make up only 8% of Earth’s crust
However, minerals like gypsum, calcite, and halite are major components in sedimentary rock
Many others are important economically
Major nonsilicate minerals belong to 3 groups:
Carbonates
Sulfates
Halides

12. Carbonates Simpler structure compared to silicates
Composed of one carbonate atom and another positive ion
The most common carbonate is calcite
Calcite is a major component in limestone and marble
Limestone is used for roads, building stones, and main ingredient in Portland cement
Marble is used decoratively and is very expensive

13. Halite and Gypsum Halite is the mineral name for common table salt
Both are commonly found in thick layers that are the last vestiges of ancient seas that have long since evaporated
Halite is the mineral name for common table salt
Gypsum (calcium sulfate + water bound into the structure) is the mineral of which plaster and other similar building materials are composed