1. Atoms Atoms – basic building blocks for all earth materials; consist of 3 basic components: protons, neutrons, electrons Atoms – basic building blocks for all earth materials; consist of 3 basic components: protons, neutrons, electrons

2. Atoms combine to form Elements Elements – fundamental component that can not be broken down into other substances by ordinary chemical processes Elements – fundamental component that can not be broken down into other substances by ordinary chemical processes Elements combine to form minerals Elements combine to form minerals

3. General Facts About Minerals 2,000 + minerals have been identified 2,000 + minerals have been identified A few are “native elements” -- made of only one element, such as sulfur, gold. copper, and graphite (carbon) A few are “native elements” -- made of only one element, such as sulfur, gold. copper, and graphite (carbon) Most are compounds, especially the silicate group (Si, O). Most are compounds, especially the silicate group (Si, O). Other important groups are oxides, carbonates, and sulfides. Other important groups are oxides, carbonates, and sulfides.

4. Gold (Au) Silver (Ag) Platinum (Pt) Diamond (C) Graphite (C) Sulfur (S) Copper (Cu) MINERALS NATIVE ELEMENTS Copper Silver Gold

5. Mineral Criteria 1. Crystalline solid 1. Crystalline solid 2. Naturally occurring 2. Naturally occurring 3. Have a definite chemical composition 3. Have a definite chemical composition 4. Inorganic 4. Inorganic

8. Minerals are identified by their Physical Properties Crystal Form Crystal Form Color Color Streak Streak Luster – metallic, non-metallic Luster – metallic, non-metallic Hardness – Moh’s Hardness Scale (1-10) Hardness – Moh’s Hardness Scale (1-10) Cleavage Cleavage Fracture Fracture Specific Gravity Specific Gravity Others Others

9. A mineral’s physical properties are controlled by its internal arrangement of atoms regularly repeating, orderly pattern regularly repeating, orderly pattern

10. The most common crystalline structure Silica-oxygen tetrahedron – basic building block for silicate minerals Silica-oxygen tetrahedron – basic building block for silicate minerals

11. Silica tetrahedron combine several different ways Five major types of silicate minerals based on their structure A) Isolated tetrahedron B) Single chain C) Double chains D) Sheet silicates E) 3-D framework silicates

14. Minerals can have the same chemical composition (Carbon) but different physical properties because of their crystal structure Diamond Graphite

15. COLOR Color is not usually a definitive property of a mineral. Color is not usually a definitive property of a mineral. Some minerals have characteristics colors Some minerals have characteristics colors Others vary due to chemical differences or impurities (atoms mixed inside the main elements) Others vary due to chemical differences or impurities (atoms mixed inside the main elements) However most minerals have a variety of colors. However most minerals have a variety of colors.

16. Some Colors of Quartz

17. STREAK For opaque minerals, if you rub the sample across a streak plate, it will leave a colored powder. This streak is distinctive for minerals and is used to identify minerals. For opaque minerals, if you rub the sample across a streak plate, it will leave a colored powder. This streak is distinctive for minerals and is used to identify minerals.

18. Varieties of Hematite – all same color streak

19. HARDNESS – Mineral’s resistance to scratching. Minerals with higher numbers will scratch minerals below

20. LUSTER Describes how light reflects off the surface Describes how light reflects off the surface Categories: Metallic or non-metallic Categories: Metallic or non-metallic Metallic does not mean shiny Metallic does not mean shiny Non-metallic: vitreous or glassy; silky; resinous; pearly; greasy; waxy, dull; earthy Non-metallic: vitreous or glassy; silky; resinous; pearly; greasy; waxy, dull; earthy

21. Examples of metallic luster

22. Pyrite (FeS 2 ) Galena (PbS) More Examples of Metallic Luster PYRITE GALENA

23. Example of non-metallic luster Vitreous--quartz Vitreous--quartz

24. Example of non-metallic luster Silky--example plagioclase feldspar Silky--example plagioclase feldspar

25. Non-metallic and metallic luster – earthy hematite – metallic hematite

26. Cleavage and Fracture Some minerals split along flat surfaces when struck hard--this is called mineral cleavage Some minerals split along flat surfaces when struck hard--this is called mineral cleavage Other minerals break unevenly along rough or curved surfaces--this is called fracture Other minerals break unevenly along rough or curved surfaces--this is called fracture A few minerals have both cleavage and fracture ( mica ) A few minerals have both cleavage and fracture ( mica )

27. Cleavage FLUORITE HALITE Halite (NaCl) Fluorite (CaF 2 )

29. Cleavage BIOTITE MUSCOVITE

30. Rose Quartz – Conchoidal Fracture

31. Conchoidal Fracture - Quartz Obsidian

32. DENSITY / SPECIFIC GRAVITY This is the ratio of the density of the mineral to the density of water. This is the ratio of the density of the mineral to the density of water. Weight Air/(Weight Air-Weight in water) = specific gravity Weight Air/(Weight Air-Weight in water) = specific gravity

33. Acid Test for Carbonates Special Characteristics: Special Characteristics: Carbonates react with dilute HCl and other acids by fizzing or bubbling (releasing CO2 gas) Carbonates react with dilute HCl and other acids by fizzing or bubbling (releasing CO2 gas)

34. MINERALS NONSILICATE MINERALS CARBONATES Carbonate ion (CO 3 2- ) is prominent in minerals. Has -2 charge. Combines readily with positive ions. Bonds generally weak. Minerals are soft (3-4). Minerals are soluble in acidic water. Leads to cave development. Calcite (CaCO 3 ) Dolomite (CaMg(CO 3 ) 2 ) DOLOMITE CALCITE

35. Less than a dozen are common in most rocks Quartz Quartz Feldspar (group) Feldspar (group) Muscovite (silver white mica) Muscovite (silver white mica) Biotite (black mica) Biotite (black mica) Calcite Calcite Pyroxene Pyroxene Olivine Olivine Amphibole (group) Amphibole (group) Magnetite, limonite, and other iron oxides Magnetite, limonite, and other iron oxides Pyrite Pyrite

36. Common uses include: Aluminum--packaging, transport, building Aluminum--packaging, transport, building Beryllium--gemstones, fluorescent lights Beryllium--gemstones, fluorescent lights Copper--electric cables, wires, switches Copper--electric cables, wires, switches Feldspar--glass and ceramics Feldspar--glass and ceramics Iron--buildings, automobiles, magnets Iron--buildings, automobiles, magnets Calcite--toothpaste, construction Calcite--toothpaste, construction