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Ch 5- Minerals. Minerals. Ch 5, p. 103 QOD- What is a mineral?. Question set- #1-10 today. Show me when you finish 1-10 and then keep in notebook. REMEMBER: LAB TOMORROW! Missing contracts Shoes & Lab Safety Rules. Sep 14.
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Minerals Ch 5, p. 103 QOD- What is a mineral?
Question set- #1-10 today. Show me when you finish 1-10 and then keep in notebook. • REMEMBER: LAB TOMORROW! • Missing contracts • Shoes & Lab Safety Rules
Sep 14 • QOD- What are the seven physical properties used to identify minerals? • Review of Identifying Metals Lab • Video Clip- Minerals • Notes & Questions- ch 5 minerals • Keep the questions in your notebook • Test 4 – 5 Wednesday
Sep23 Earth Systems • Test- chapters 4 & 5 is Thursday! • Today- • Ch 5 notes • Tomorrow- • Last day to turn in mineral projects • Wednesday: Crystal Growing-! • Bring 1 pound (2 cups) sugar • Wear close toed shoes • Thursday- test ch 4-5
Is it a Mineral? • Is it inorganic? • Does it occur naturally? • Is it a crystalline solid? • Consistent chemical composition? • Must answer yes to all 4 questions for it to be a mineral
10 Most common minerals • Quartz • Calcite • Orthoclase • Dolomite • Plagioclase • Halite • Muscovite • Gypsum • Biotite • Ferromagnesianminerals • These make up 90% of Earth’s mass
Mineral Groups • Silicates • 96% of Earth’s crust • Contains Si (silicon) and O(oxygen) quartz • Can have other elements also • Feldspar – • Orthoclase if K (potassium), • Plagioclase if Na (sodium) or Ca (calcium) • Ferromagnesian minerals – rich in Fe (iron)
Orthoclase - Lorenzenite Plagioclase - Albite Ferromagnesian - Olivine
Mineral Groups • Nonsilicate Minerals • Do not contain Si and O • Can contain one or the other, but not both • Six groups • Carbonates • Native elements • Halides • Oxides • Sulfates • Sulfides
Carbonate - Calcite Halide - Halite Native Elements - Gold Oxides - Hematite Sulfides - Galena Sulfates - Gypsum
Crystalline Structure • Crystal – atoms, ions, or molecules are arranged in a regular, repeating pattern • Silicate crystal structure • Silicon – oxygen tetrahedron • 1 Si with 4 O’s around it (illustrated in the book) • Basic building block of silicates • Can be connected 6 different ways
Crystalline Structure • Nonsilicate crystals • Diverse chemical composition leads to variety of crystal structures • Cubes, hexagonal prisms… • Crystal structure influences physical properties • Native elements are dense due to compact crystal structure
Physical Propertiesof Minerals • Mineralogist • Examine, analyze, and classify minerals • Result from chemical composition and crystal structure • Can be useful in identifying minerals
Physical Properties • Color • Not reliable for ID purposes (subjective) • Small amount of impurities can affect color • Weathered surfaces may hide color • Only look at fresh surfaces
Physical Properties • Streak • Color of mineral in powder form • Streak plate – unglazed ceramic tile • Streak color may differ from mineral color • Metallic minerals – darker streak • Nonmetallic minerals – lighter streak
Physical Properties • Luster • Light reflected from mineral’s surface • Metallic luster – shiny surface • Nonmetallic luster • Glassy • Waxy • Pearly • Brilliant • Dull / Earthy
Physical Properties • Cleavage / Fracture • Cleavage • Splitting along specific lines of weakness • Forms smooth, flat surfaces • Fracture • Break unevenly into pieces • Forms curved, irregular surfaces • Conchoidal fractures – curved surface
Physical Properties • Hardness • Ability to resist scratching • Mohs Hardness Scale • Scale of 1 to 10 • 1 = Talc 10 = Diamond • Glass is about a 5
Physical Properties • Crystal Shape • 6 Basic shapes • Certain minerals always form crystals with the same shape • Density • Ratio of mass to volume • Can help identify minerals
Physical Properties • Fluorescence and phosphorescence • Chatoyancy and asterism • Double refraction • Magnetism • Radioactivity
Diamond fluorescence with ultraviolet light Phosphorescence – over time on a watch face
Chatoyancy Asterism
Crystal Growing Lab- Wedn. • Bring 1 pound (2 cups) sugar • Wear close toed shoes