Minerals are naturally occurring inorganic solids with a specific chemical composition and crystalline structure. They form through natural geological processes in the Earth's crust and mantle. The most common minerals are silicates containing oxygen, silicon, aluminum, iron, calcium, sodium, and potassium. Minerals can form from the cooling of magma or crystallization from solution. Identification of minerals is done through analysis of physical properties like color, luster, hardness, cleavage, and other characteristics.

1. MINERALS acloutier copyright 2011 acloutier copyright 2011

2. Essential questions : What is a mineral ? How are minerals formed ? naturally occurring inorganic (never alive, or part of a living organism) solid with a specific chemical composition a definite crystalline structure acloutier copyright 2011

3. Naturally occurring and inorganic nature forms minerals in a natural processes if there were no humans on Earth, these minerals would still be forming naturally ( if people create a mineral in a Lab it is a synthetic mineral like a cubic zircon) inorganic they are not alive, or part of something that once was alive. * coal is not a mineral because its original matter was once alive (peat plants) sugar crystals are not minerals either because they were once part of a sugar cane plant. acloutier copyright 2011

4. Solid with a specific composition only solids are considered minerals no gas or liquid can be considered a mineral each type of mineral has a specific composition unique to that mineral many are compounds some are elements such as gold, silver, sulfur, copper some minerals have a certain ratio or proportion of elements for them to be considered that mineral , and the overall composition remains uniform acloutier copyright 2011

5. CRYSTALS are a solid arranged in regular geometric patterns that are repeated over and over Six major groups of crystals Cubic Orthorombic Tetragonal Hexagonal Monoclinic Triclinic acloutier copyright 2011

6. Very detailed site to learn more about crystals and minerals www.yale.edu/ynhti/pubs/A5/vanwagner.html acloutier copyright 2011

7. Minerals from magma magma is molten materials found beneath Earth’s surface density differences in the lithosphere affect what minerals will form as the magma cools chemicals in the magma stop flowing freely and begin to interact chemically forming minerals the rate at which minerals cool, determines the size of the crystal the longer cooling rate > larger crystals fast cooling rate > smaller crystals acloutier copyright 2011

8. Minerals from solution water can dissolve only so much of a solid before the water becomes saturated in nature this becomes a supersaturated solution once supersaturated or overfilled with molecules of the former solid, crystals precipitate or drop out of solution evaporation can also form minerals by removing the water molecules from solutions these are called evaporites acloutier copyright 2011

9. Mineral Groups ~ 3,000minerals are found on Earth’s crust Most common are called “rock forming”~90 minerals form naturally in Earth’s crust Oxygen makes up 46.6 % Silicon 27.7 % Aluminum 8.1 % Iron 5 % Calcium 3.6 % Sodium 2.8 % Potassium 2.6 % Magnesium 2.1 % Other 1.5% acloutier copyright 2011

10. Silicates > oxygen O and silicon Si minerals that contain silicon and oxygen are called silicate minerals oxygen is the most abundant element in Earth’s crust followed by silicon 96 % of the minerals found on Earth belong to the silicates. one silicon atom is bonded to four oxygen atoms in a tetrahedron crystal this crystal shape has the ability to share oxygen with other tetrahedron molecules acloutier copyright 2011

11. Single chains, double chains and sheets of tetrahedrons of silicates can combine chemically in many ways. Quartz is chemically bonded in a very complex and strong crystal structure Quartz is highly resistant to chemical weathering Mica separates easily in sheets because of it’s sheet tetrahedron structure acloutier copyright 2011

12. Carbonates carbon and oxygen CO 3 Carbonates are minerals composed of one or more metallic element with carbonate compounds CO 3 limestone coquina marble malachite azurite < very colorful > acloutier copyright 2011

13. acloutier copyright 2011

14. Identifying Minerals >the field method Geologist depend on simple test to identify minerals: Color > most notable but can’t be certain Luster > how the mineral reflects light (dull, pearly, metallic, waxy, silky) Texture > how does it feel to touch? (smooth, rough, greasy, soapy, glassy) Streak > when the mineral is rubbed against a white or black porcelain tile a powder streak is left in it. This is the true color of the mineral ( sometimes the power streak does not match what we see) One test does not identify a mineral * acloutier copyright 2011

15. Color acloutier copyright 2011

16. Luster acloutier copyright 2011

17. Streak rub the mineral against an unfinished porcelain plate acloutier copyright 2011

18. Moh’s Scale of Hardness Hardness the measure of how easily a mineral can be scratched acloutier copyright 2011

19. Diamonds are a 10 Mohs Scale of Hardness Talc is the softest mineral at number 1Mohs Scale baby powder has talc minerals in it acloutier copyright 2011

20. Cleavage & Fracture how a mineral breaks The atomic structure of a mineral determines how it will break CLEAVAGE >if a mineral breaks or splits relatively easy along one or more flat plans it has cleavage Mica is an example Halite has cubic cleavage (salt crystal) FRACTURE >Quartz breaks along rough, jagged edges Conchoidal fracture resembles an arch or “ clam shell shaped” break pattern Obsidian and flint uniquely break this way acloutier copyright 2011

21. Special Properties of Minerals Magnetic Double refraction acloutier copyright 2011

22. Fluorescent minerals acloutier copyright 2011

23. Ore … a mineral is an ore if… It contains a useful substance that can be mined for a profit The ore rutile contains the element titanium , used in sports equipment and medicine to fix broken bones acloutier copyright 2011

24. Gems rare and beautiful like you ! acloutier copyright 2011

25. the end acloutier copyright 2011