Rocks and minerals for grade 11; Earth and life sciences
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The document outlines the properties and classifications of minerals and rocks, including physical and chemical characteristics. It describes minerals as naturally occurring inorganic solids with specific properties, and discusses their importance and uses. Additionally, it categorizes rocks into igneous, sedimentary, and metamorphic types based on their formation processes and properties.
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Rocks and minerals for grade 11; Earth and life sciences
- 2. Learning Outcomes • I can identify the physical properties of minerals • I can identify the chemicaL properties of minerals. • I can identify some minerals and their uses. • I will appreciate the importance of conserving mineralsI can identify and describe the different properties of rocks.
- 3. Minerals Minerals - naturaly formed, generally inorganic, crystalline, solid and has a definite chemical composition. building blocks of rocks Mineralogy - Branch of Geology that deals with the study of Minerals There are about 3,000 known minerals, of that 20 minerals make up most rocks
- 4. Physical Properties of Minerals - can be used to easily identify a mineral. 1. Color 2. Streak 3. Hardness 4. Cleavage and Fracture 5. Crystalline structure 6. Transparency or diaphaneity 7. Magnetism 8. Tenacity 9. Luster 10. Odor 11. Specific Gravity
- 5. Physical Properties of Minerals 1. Color - usually the property used to identify minerals easily. It is the result of the way minerals absorb light. Some Colors of Quartz
- 7. Physical Properties of Minerals 2. Streak - is the color of the mineral in powder form. 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.
- 8. Varieties of Hematite – all same color streak
- 10. Physical Properties of Minerals 3. Hardness - refers to the measure of the mineral’s resistance to scratching. Minerals with higher numbers will scratch minerals below. To measure the relative hardness of minerals, the Moh's scale is used.
- 11. Physical Properties of Minerals 4. Cleavage and Fractures - used to describe how minerals break into pieces. Some minerals split along flat surfaces (called cleavage planes) when struck hard--this is called mineral cleavage Other minerals break unevenly along rough or curved surfaces--this is called fracture A few minerals have both cleavage and fracture ( mica )
- 13. FLUORITE HALITE Halite (NaCl) Fluorite (CaF2) Cleavage – due to weak bonds in the crystal structure
- 16. Rose Quartz – Conchoidal Fracture
- 17. Conchoidal Fracture - Quartz Obsidian
- 19. Physical Properties of Minerals 5. Crystalline structure - crystal lattice, tells how a mineral’s crystals are arranged. A hand lens is a necessary tool in checking for crystalline structure. crystal solid - form regular repeating three dimensional crystal lattice amorphous solid - forms aggregates that have particular order or arrangement
- 20. Physical Properties of Minerals 6. Transparency or diaphaneity - indicates the extent of light that can pass through the mineral.
- 21. Physical Properties of Minerals 7. Magnetism - indicates the ability of a mineral to attract or repel other minerals. 8. Tenacity - level of resistance or reaction of minerals to stress such as crushing, bending, breaking, or tearing. 9. Luster - refers to the reaction of a mineral to light. It determines how brilliant or dull the mineral is. Categories: Metallic or Non-metallic Metallic – luster of metal – shines like a hard metal Many non-metallic minerals are SHINY because they are transparent or semi-transparent
- 22. Examples of metallic luster
- 23. Pyrite (FeS2) Galena (PbS) More Examples of Metallic Luster PYRITE GALENA
- 24. Example of non-metallic luster • Vitreous--quartz
- 25. Example of non-metallic luster • Silky--example plagioclase feldspar
- 26. Non-metallic and metallic luster – earthy hematite – metallic hematite
- 27. Physical Properties of Minerals 10. Odor - -a distinct smell of a mineral that is usually released from a chemical reaction when subjected to water, heat, air or friction. 11. Specific Gravity - is a measure of the density of a mineral. Determines how heavy the mineral is by its weight to water.
- 28. Chemical Properties of Minerals Another way of identfying and classifying minerals is according to their chemical compositon. This classification was first used in 1848 by James Dwight Dana (1813- 1895). 1. Silicate class 5. Oxide class 2. Carbonate class 6. Sulphide class 3. Sulphate class 7. Phosphate class 4. Halide class 8. Native element class
- 29. Chemical Properties of Minerals 1. Silicate Class - largest and most abundant group containing Si and O with some Al, Mg, Fe, and Ca. (Ex. feldspar, quartz, pyroxene, mica, garnet. olivine and amphibole
- 30. Chemical Properties of Minerals 2. Carbonate class - mostly found depositedin marine environments. 3. Sulphate Class - forms in areas with high evaporation rates and where salty waters slowly evaporate. (Ex. anhydrite, celestine, barite, gypsum) 4. Halide class - contains natural salts includes fluorite, halite, sylvite and sal ammoniac components. Usually form in lakes, and sal ammoniac components.
- 31. Chemical Properties of Minerals • 5. Oxide class - is a diverse class. In science, these minerals are important as thet carry histories of changes in Earth's magnetic field. They are formed as precipitates close to Earth's surface or as oxidation products of minerals during the process of weathering. • 6. Sulphide class - has important metals such as copper, lead and silver which are considered economically significant.
- 32. Chemical Properties of Minerals 7. Phosphate class- contains minerals with phosphorus. Considered as important biological mineral found in teeth and bones in many animals. 8. Native element class - contains metals and intermettalic elements, semimetals nonmetals or natural alloys and constituents of a few rare meteorites.
- 33. Rocks - are natural substances consisting of aggregate minerals clumped together with other materials through natural processes. Rocks, like some materials, are products of a natural cyclic process.
- 34. Properties of Rocks 1. Rocks exhibit different properties. As to color, rocks may be dark, light, reddish, ggray, brown, yellow o even black. 2. Rocks differ in texture: some are fine, others are rough. 3. Some are glossy in appearance and smooth to touch. 4. Most rocks are hard, others are brittle.
- 35. Classification of Rocks 1. Igneous rocks - derived from the Latin word ignis meaning “fire” are crystallized from magma or molten or partially molten volcanic materials that came from within Earth. Magma rises from the asthenosphere or at the base of the crst through volcanoes or any cracks and fisures on Earth's surface. When it reaches the sface of Erth. thr molten volcanic material is called lava. (granite, rholite, diorite, andesite, basalt, gabbro)
- 36. Importance of Igneous Rocks • contains fossils that are evidences of geologic past • coal, petroleum and natural gas are major energy source • iron , aluminum and manganes are used in the construction industry.
- 37. Classification of Rocks 2. Sedimentary rocks - frm the root word sediments which means “remaining particles” are rocks that have formed from the deposition of different materials on Earth's surface. They come from preexistinf rocks or pieces of dead organisms that have been “lithified” or cemented by natural processes. (limestone, conglomerate, haite, calcite, sandstone, limestone and gypsum)
- 38. 2 major groups of sedimentary rocks 1. clastic - form from the accumulation and lithification of sediments derived from the breakdown of pre-existing rocks. They are further classified according to dominant grain size. 2. nonclastic - derived from sediments that precipitated from concentrated solutions (e.g. seawater) or from the accumulation of biologic or organic material (e.g. shells, plant material). They are further classified on the basis of chemical composition.
- 39. Classification of Rocks 3. Metamorphic rocks - meta means “change”” and morph means “form” are rocks derived from gneous or sedimentary rocks that were exposed to high pressure, high temperature or a combination of both, deep below te surface of Earth. Because of this exposure, some of the minerals in these roocks undergo chemical and physical changes.