Understanding Minerals: Definitions, Characteristics, and Uses

1. Chapter 3 Minerals

2. 3.1 Minerals • What is a Mineral? • Definition – a naturally occurring, inorganic solid with a definite structure and composition • All minerals share five characteristics • Inorganic and Naturally Occurring Minerals • 1st characteristic – all minerals form from natural processes

3. 3.1 Continued • 2nd characteristic – minerals are inorganic • Not alive, never were, and not formed by life processes • Do not contain carbon • Mineral resource – term used by miners that means anything taken from the ground that has commercial value

4. 3.1 Continued • Crystalline Solids • 3rd characteristic – all are solids • Have definite volume and shape • 4th characteristic – every mineral is an element or compound with a chemical composition unique to that mineral

5. 3.1 Continued • 5th characteristic – atoms in a mineral are arranged in a pattern that is repeated over and over again • Mineraloid – a mineral-like substance that does not have atoms arranged in a definite structure

6. 3.1 Continued • The Structure of Minerals • Crystal – a solid in which the five atoms are arranged in repeating patterns • Know table 3-1 • Know the crystal pattern and examples

7. 3.1 Continued • Crystals • The size of the crystal formed depends on the space it has to grow in • Small area the crystals will be small • Open area the crystals will be large

8. 3.1 Continued • Mineral Compositions and Groups • 90 elements are found in the Earth’s crust • Only 8 elements make up 98% of the Earth’s crust • Of the 4000 minerals, only a few dozen are common • Formed from the 8 common elements • Most of the rock-forming minerals are silicates

9. 3.1 Continued • Silicates • Are minerals that contain silicon and oxygen and usually one or more other elements • Silicone and oxygen are the most abundant elements in the Earth’s crust • Other minerals are classified based on their composition

10. Major groups of minerals Carbonates Oxides Sulfides Sulfates Halides Hydroxides Phosphates Native elements 3.1 Continued

11. 3.2 Mineral Identification • Physical Properties • Appearance • What the mineral looks like • Texture, color, and other visual observations • Hardness • How easily can the mineral be scratched

12. 3.2 Continued • Diamonds are the hardest mineral • Diamonds can only be cut by other diamonds • Measured on a scale of 1 to 10 called Moh’s hardness scale • 1 is the softest and 10 is the hardest • Use common objects with known hardnesses to determine unknown minerals hardness

13. 3.2 Continued • Luster • Describes how light is reflected from a mineral’s surface • Defined as metalic or nonmetallic • Metalic – shine bright like a metal • Nonmetallic – dull and does not shine like a metal

14. 3.2 Continued • Color • Some minerals have a distinctive color • Most of the time color is not the determining factor to identifying the mineral

15. 3.2 Continued • Streak • When the mineral is dragged across a surface, it will leave behind a powder • Main test used to distinguish between pyrite and gold • Only works with minerals softer than the unglazed porcelain tile

16. 3.2 Continued • Cleavage and Fracture • The way a mineral breaks apart will leave behind a distinctive pattern • Cleavage – when a mineral breaks into smooth flat surfaces • Fracture – those minerals that break with rough or jagged edges

17. 3.2 Continued • Other Properties • Some minerals have properties that are unique only that mineral • Magnetite – has a magnetic properties • Calcite – when light passes through it you see double images

18. 3.3 Uses of Minerals • Gems • Properties of Gems • Are highly valuable minerals • Usually valuable because they are rare or have a high economic demand • Usually bright and colorful • Usually have a crystal patterns that allows the mineral to be cut into different patterns and be polished

19. 3.3 Continued • Ores • A mineral that contains a useful substance that can be mined for a profit • Aluminum comes from the mineral ore bauxite • The products from ores are worth more than the ore itself

20. 3.3 Continued • Waste Rock Removal • Waste rock is the unwanted material that is mined with the ore • Must be removed before the ore can be mined • Once the waste rock removal cost is higher than the value of the mineral being mined will no longer be classified as an ore

21. 3.3 Continued • Types of ores • Iron from hematite • Zinc from sphalerite • Copper from chalcophyrite • Malachite and azurite are gemstone ores of copper

22. 3.4 Uses of Titanium • Titanium • Is a durable, lightweight metal derived from minerals such as ilmenite or rutile • Properties of Titanium • Durable, lightweight, nontoxic

23. 3.4 Continued • Uses of Titanium • Hip replacements • Wheelchairs • Tennis rackets • Airplanes • automobiles

24. 3.4 Continued • Ilminite and Rutile • Two types of titanium ores • Methods used to remove titanium from its ores • First method • Ilminite is dissolved in sulfuric acid • Produces titanium dioxide and iron sulfate

25. 3.4 Copntinued • Second method • Rutile is combined with chlorine at high temperatures • Produces titanium tetrachloride “tickle” • Second method is becoming more popular because the iron sulfate is harmful to the environment