Transcript Slide 1
Aim: What is a Mineral? Do Now: Minerals are used in everyday life. In your notebooks, try to brainstorm about ways minerals are used by you and me every day. I. Minerals: Minerals are classified as… a. Naturally occurring – Forms by natural geologic processes. b. Solid substance c. Orderly crystalline structure – atoms are arranged in an orderly and repetitive manner. Fluorite d. Definite chemical composition – most are made up of two or more elements. e. Generally considered Inorganic – not living (exception calcite, which comes from living things). Garnet II. How do Minerals Form? There are 3 major processes by which minerals from: 1. Crystallization Galena crystallize = to form a crystal - hot material (magma/lava) cools, - elements within the combine (come together) and harden to form minerals. 2. Precipitates/Evaporites - solid substances are dissolved in water - When the water evaporates, these solids are left behind to form crystals. Like Rock Candy or the ring around your bathtub Salt Flat - Halite Limestone Cave 3. Hydrothermal Solutions - Very hot solutions cause chemical reactions with existing minerals to form new minerals. Pyrite Quartz III. Tetrahedral Crystalline Structure - Silicon and Oxygen combine to form a structure called the Silicon-Oxygen Tetrahedron. **This structure is found in Quartz and makes it the most abundant mineral. Review Questions: 1) What are the five characteristics of all minerals? Minerals are naturally occurring, inorganic, solids, with definite crystal shape and definite composition. 2) Where does the material come from to undergo crystallization? The material comes from the inside of the Earth or a volcanic eruption. The material has to be extremely hot! 3) Explain the process of the formation of a precipitate. Material needs to be dissolved in water. Later, the water is evaporated leaving the mineral behind. Solid materials can not be evaporated like water. Aim: What properties do minerals have? Do Now: How can a scientist tell the difference between different minerals? List some of the properties you would look for to classify a mineral. Use your ESRT page 16 to help determine useful properties. I. Properties of Minerals Depend on: 1) The chemical composition of the mineral. (the elements) 2) How the mineral’s atoms are arranged internally (structure). **All mineral properties depend on the atoms that make-up the mineral** Non-Metallic We will take notes on each section of this table Take out Page 16 of your ESRT 1. Color (least significant property) - Small amounts of different elements (impurities) can give the same mineral different colors. Why is color the least significant property? Quartz 2. Streak - the color of a mineral in its powdered form. - found by rubbing a mineral across a streak plate (a piece of porcelain.) - A minerals streak is identified as either; Color – any color Colorless – clear, white or no streak 3. Luster - describes how light is reflected from the surface of a mineral. What words would you use to describe non-metallic minerals? Metallic Pyrite Galena vs. Non-Metallic Sulfur Feldspar 4. Crystal Form - the visible expression of a mineral’s internal arrangement of atoms. Garnet Quartz Calcite 5. Hardness - the resistance of a mineral to being scratched. - Mohs scale consists of 10 minerals arranged from 10 (hardest) to 1 (softest). - determined using a glass plate. How to find the hardness: • Hold the glass plate flat on the table. • Use a clean un-scratched surface. • The mineral should be scratched against the glass plate once with some pressure. 1. If it scratches the glass, then the mineral is harder 2. If it doesn’t scratch the glass, then the mineral is softer. Copy these last two for your notes on hardness. 6. Cleavage - the tendency of a mineral to break (cleave) along flat, even surfaces. - Minerals appear to have right angles, flat surfaces, boxed appearance. Mica Calcite 7. Fracture - the uneven breakage of a mineral. Sulfur Quartz 8. Distinctive Properties of Minerals - Some minerals can be recognized by other distinctive properties (magnetism, smell) - Effervescence (bubbling) using Hydrochloric Acid indicates the presence of calcium (Calcite.) Closure Take a blue lab from the back top bin. With your partner, begin to answer the vocabulary. REMEMBER you are trying to do this from what you learned and recall, NOT from copying it out of your book.