Minerals PDF

Minerals OBJECTIVES: At the end of the discussion, the students will be able to:  Describe the criteria of a minerals.  Knowthe importance and use of minerals to human development.  Developa systematic way of identifying minerals. The Earth’s crust is made up of two things: Mine...

Minerals OBJECTIVES: At the end of the discussion, the students will be able to:  Describe the criteria of a minerals.  Knowthe importance and use of minerals to human development.  Developa systematic way of identifying minerals. The Earth’s crust is made up of two things: Minerals and Rocks  The Earth’s crust is made up of two things: Minerals and Rocks Gneiss Coal Scoria Minerals are Rocks are individual crystals combinations of the same stuff of minerals naturally occurring each is unique aggregate of minerals composed of elements  By knowing its definition can you be able to identify that a certain material is a mineral?  Examples of Minerals: Quartz Iron Calcite Hematite Calcite Diamond Examples: Amethyst Calcite Garnet Galena Gold Pyrite A. What is a mineral? Mineral Characteristics shared by all minerals: 1. Natural – occurs naturally – NOT manmade What is a mineral? 2. Inorganic – Is not alive – Was never alive What is a mineral? 3. Crystalline – Atoms are arranged in an orderly pattern mineraloids is a mineral-like substance that does not demonstrate crystallinity amorphous Mineraloids mercury opal pumice obsidian What is a mineral? 4. Definite chemical composition – Chemical formula – SiO2 is Quartz What is a mineral? 5. Solid – Not a gas, not a liquid How will we remember this? Natural Inorganic Crystalline Definite chemical composition Solid Mineral Characteristics shared by all minerals: Now I Can Define mineralS! Natural Inorganic Crystalline Definite chemical composition Solid  Physical properties B. Physical Properties of Minerals 1. Color – First impression – Not very reliable because lots of minerals can occur in many different colors  Quartz Purple Amethyst  Clear Fluorite Blue Green Purple Physical Properties of Minerals 2. Streak – The TRUE color of a mineral – Color of a mineral’s in powder Streak Minerals with a hardness greater than “7” usually don’t create a streak on the streak plate because they are harder than the Porcelain tile (unless the streak plate is specially made).  Physical Properties of Minerals 3. Hardness – A mineral’s resistance to being scratched – Mohs Hardness Scale from 1-10 Hardness depends on how “tightly packed” the atoms are  Mohs Hardness Scale 1 Talc Softest 2 Gypsum 3 Calcite 4 Fluorite 5 Apatite 6 Potassium feldspar 7 Quartz 8 Topaz 9 Corundum 10 Diamond Hardest  Physical Properties of Minerals 4. Cleavage – Splits along definite planes “Cleav” = to split Cleaver Physical Properties of Minerals 5. Fracture – Breaks irregularly, jagged edges Fracture Physical Properties of Minerals 6. Luster – How light shines off a mineral – Metallic or Nonmetallic Luster Nonmetallic Metallic translucent, pearly, waxy, vitreous/glassy, dull, or earthy metallic earthy Galena Goethite vitreous waxy quartz chalcedony  pearly talc Physical Properties of Minerals: Used for Color Identification (I.D.) Streak Hardness Cleavage Fracture Luster C. Special Properties 1. Magnetism – Attracted to a magnet – Contains IRON, cobalt, or nickel Special Properties 2. Double refraction – Looking through it, you see “double” – Ex. Calcite Special Properties 3. Fluorescence – Glows under ultraviolet (UV) light Fluorescence under ultraviolet, UV light  Special Properties 4. Phosphorescence – Continues to glow even after the UV light has been removed Special Properties 5. Piezoelectric – Electricity is generated from Pressure – Example: Quartz Special Properties Magnetism Double refraction Fluorescence Phosphorescence Piezoelectric  USES OF MINERALS: QUARTZ MAKES GLASS. DIAMONDS MAKE JEWELRY. HEMATITE CAN BE USED TO MAKE ART. MANY THINGS THAT WE SEE AND USE EVERY DAY ARE MADE FROM IRON. THANK YOUYOU Piezoelectric (Pressure=Electricity) D. Identification Tests 1. Hardness 2. Streak (True Color) 3. Acid Test – Use hydrochloric acid – Tests for carbonate (calcite) Caves can form in rocks with calcite, like here in Harrisonburg! Acid in groundwater dissolves the calcite