1. Introduction to Minerals

2. Objectives Define mineral. Compare the two main groups of minerals.
Identify the six types of silicate crystalline structures.
Describe three common nonsilicate crystalline structures.

3. Introduction to Minerals

4. Why study minerals
Made and remade on Earth’s surface, oceans, and in the layers inside of Earth.
They give us insight into Earth’s historical development and dynamics.
Essential to industry
Iron, copper, aluminum and magnesium

5. Why study minerals? Important to economy Environmental Impacts
Cost of rare to find “gem quality” minerals
High cost
Environmental Impacts
Extraction of minerals

6. Minerals Seen in our daily lives.
Many of you have already used a mineral today.
Toothpaste
Mica – sparkles
Car
Hematite – iron ore – steel (skyscrapers also)
Makeup (especially shimmer and glitter)
Mica and talc

7. Rarity
Some minerals are rare and highly prized for their characteristics.
Gold – conductivity, resistance to corrosion, high luster.
Diamonds – Beauty and
hardness
Some minerals are very
common.
Quartz - sand

8. What is a mineral? Nutritionist – things to be eaten
Add plant and animal life processes.
Jeweler – a stone to be cut or polished.
Geologist – a naturally occurring, inorganic compound with a fixed chemical composition and an orderly internal arrangement of atoms (IAOA).

9. Characteristics of Minerals
mineral a natural, usually inorganic solid that has a characteristic chemical composition, an orderly internal structure, and a characteristic set of physical properties.
To be a mineral, a substance must have four characteristics:
it must be inorganic—it cannot be made of or by living things;
it must occur naturally—it cannot be man-made;
it must be a crystalline solid;
it must have a consistent chemical composition.

10. Characteristics of Minerals
You can tell whether an object is a mineral by asking four questions.
Is it a nonliving material?
Is it a solid?
Does it have a crystalline structure?
Is it formed in nature?

11. Characteristics of Minerals, continued
The diagram below shows the four characteristics of minerals.

12. Crystalline Structure
Each type of mineral is characterized by a specific geometric arrangement of atoms, or its crystalline structure.
crystal a solid whose atoms, ions, or molecules are arranged in a regular, repeating pattern
One way that scientists study the structure of crystals is by using X rays. X rays that pass through a crystal and strike a photographic plate produce an image that shows the geometric arrangement of the atoms in the crystal.

13. How is a crystals shape determined?
Internal arrangement of atoms.
The arrangement of atoms is determined by the atoms of the minerals.
DEFINITE CRYSTAL STRUCTURE!
Minerals can be grouped into crystal classes or systems.

14. Crystal Systems Isometric – Cubic – look like blocks
Pyrite
Tetragonal – 4 sided pyramids, prisms
Zircon
Hexagonal – 6 sided pyramids, prisms
Beryl, quartz

15. Crystal Systems Orthorhombic – short and stubby
Topaz
Monoclinic – short and stubby with tilted faces at each end.
Gypsum
Triclinic – sharp flat edges, no right angles
Feldspar

16. Mineral Structure
To understand what a crystalline structure is, you need to know a little about the elements that make up a mineral.
Elements are pure substances that cannot be separated or broken down into simpler substances by chemical means.
92 different elements
Represented by one or two letter symbols
O = Oxygen
Si = Silicon

17. Atoms and Compounds
Atoms and Compounds Minerals may be either elements or compounds.
A compound is a substance made of atoms of two or more different elements joined by chemical bonds.
Example: Halite (NaCl)
Na is sodium
Cl is chloride

18. Kinds of Minerals
The 20 most common minerals are called rock-forming minerals because they form the rocks that make up Earth’s crust.
Ten minerals are so common that they make up 90% of Earth’s crust. These minerals are quartz, orthoclase, plagioclase, muscovite, biotite, calcite, dolomite, halite, gypsum, and ferromagnesian minerals.
All minerals can be classified into two main groups— silicate minerals and nonsilicate minerals —based on their chemical compositions.

19. Kinds of Minerals, continued
Silicate Minerals
silicate mineral a mineral that contains a combination of Silicon (Si) and Oxygen (O) and that may also contain one or more metals.
Common silicate minerals include:
quartz: the basic building block of many rocks
Feldspars: minerals that are the main component of most rocks on Earth’s surface
Micas: minerals that separate easily into sheets when they break
ferromagnesian minerals, such as amphiboles, pyroxenes, and olivines.
Silicate minerals make up 96% of Earth’s crust. Quartz and feldspar alone make up more than 50% of the crust.
Crystalline Structure is made up of some arrangement of:
4 oxygen atoms
1 silicon atom

20. Silicate Minerals
Crystal Structure yields a silicon oxygen – tetrahedron.

21. Kinds of Minerals, continued
Nonsilicate Minerals
nonsilicate mineral a mineral that does not contain compounds of silicon and oxygen
Nonsilicate minerals comprise about 4% of Earth’s crust.
Nonsilicate minerals are organized into six major groups based on their chemical compositions.
The six major groups of nonsilicate minerals are carbonates, halides, native elements, oxides, sulfates, and sulfides.

22. Classes of Nonsilicate Minerals
A mineral that is composed of only one element is called a native element.
Gold and silver are examples of native elements
Made up of only ONE element – other examples of native elements are:
Copper – Cu
Iron – Fe
Diamond – C
Native elements are used in communications and electronics equipment

23. Classes of Nonsilicate Minerals
Carbonates are minerals that contain combinations of carbon and oxygen in their chemical structure
Calcite and Dolomite are examples of Carbonates
Used in cement, building stones, and fireworks.

24. Classes of Nonsilicate Minerals
Halides are compounds that form when fluorine, chlorine, iodine, or bromine combine with sodium, potassium, or calcium.
Fluorite and Halite are examples of Halides
Halide minerals are used in the chemical industry and in detergents.

25. Classes of Nonsilicate Minerals
Oxides are compounds that form when an element, such as aluminum or iron, combines chemically with oxygen.
Corundum is an example
of an Oxide.
Oxide minerals are used to make abrasives, aircraft parts, and paint.

26. Classes of Nonsilicate Minerals
Sulfates are minerals that contain sulfur and oxygen, SO4 .
Gypsum/Selenite is an example of a Sulfate
Sulfates are used in cosmetics, toothpaste, cement, and pain.

27. Classes of Nonsilicate Minerals
Sulfides are minerals that contain one or more elements such as lead, iron, or nickel, combined with sulfur.
Galena is an example of a Sulfide.
Sulfide minerals are used to
make batteries, medicines, and electronic parts.

28. Reading Check
What compound of elements will you never find in a nonsilicate mineral?
Nonsilicate minerals never contain compounds of silicon bonded to oxygen.