MINERALS MR. WHITE ADVANCED CONTENT EARTH SCIENCE
WHO STUDIES THE EARTH S SURFACE & ITS CHANGING SHAPE? Geologists!
GEOLOGISTS STUDY minerals rocks earthquakes volcanoes plate tectonics
WHAT IS A MINERAL? A naturally occurring, inorganic solid that has a crystal structure and has a definite chemical composition Must have 5 characteristics: Naturally occurring Inorganic Solid Crystal structure Definite chemical composition
NATURALLY OCCURRING Minerals must occur naturally Cement, brick, steel, & glass are not minerals because they are manufactured by man
INORGANIC It cannot arise from materials that were once part of a living thing Ex: Coal is organic which comes from the remains of plants & animals Coal is not a mineral
SOLID Must be solid with a definite volume & shape
CRYSTAL STRUCTURE The mineral must have particles that line up in patterns that repeat over & over again
DEFINITE CHEMICAL COMPOSITION The mineral contains certain elements in definite proportions Almost all minerals are compounds, 2 or more elements combined Ex: Quartz-made of 1 atom of silicon to every 2 atoms of oxygen
HOW ARE MINERALS IDENTIFIED? Each mineral has its own set of properties used to identify it Mineral Tests include: Color Hardness Streak Luster Density Crystal Systems Cleavage & Fracture Special Properties
COLOR The color of a mineral is an easy identifiable test Color is not a reliable test for identifying minerals
Mohs Scale is used to test the mineral s hardness The scale ranks 10 minerals from softest to hardest A mineral can scratch any mineral softer than itself To test hardness we use items of known hardness to try and scratch the mineral sample HARDNESS
STREAK The streak of a mineral is the color of its powder left behind when scratched on a streak plate Often times the mineral color & the streak color are different
LUSTER Luster describes how a mineral reflects light from its surface Ex terms used to describe luster: Glassy Shiny Earthy Waxy Pearly
DENSITY Each mineral has a characteristic density Density = mass volume It is shown as mass per cubic volume Use a balance to get the mass of the mineral Place the mineral in water to get the volume Divide mass by the volume
DENSITY Density is the mass in a given space A balance is used to determine the mineral s mass & a graduated cylinder is used to determine its volume=density D=M/V
CRYSTAL SYSTEMS Six crystals systems, based on the number of angles of the crystal structures, are used to identify minerals
6 CRYSTAL SYSTEMS
CLEAVAGE & FRACTURE The way a mineral breaks can help to identify it Cleavage-a mineral that splits easily along flat surfaces. For Example: mica Fracture-a mineral that splits apart in an irregular way. For Example: quartz
CLEAVAGE OR FRACTURE?
SPECIAL PROPERTIES Minerals can also be identified by special features Ex: Fluorescence-minerals that glow under ultraviolet light
SPECIAL PROPERTIES Optical (visual) properties- Calcite bends light to produce a double image Magnetism- Magnetite attracts iron staples. Reactivity- Aragonite reacts chemically to acids. Radiation- Uranium emits radon gas.
HOW DO MINERALS FORM? 1. They crystallize from melted (liquid) materials like magma & lava 2. They crystallize when certain materials are dissolved in water
HOW ARE MINERALS USED? Minerals are used in everything from talcum powder to brilliant gemstones
What is an ore? ORE- A MINERAL OR ROCK IS AN ORE IF IT CONTAINS A USEFUL SUBSTANCE THAT CAN BE MINED. Hematite is an iron ore. Bauxite is an aluminum ore.
TALC talcum powder crayons paints soaps
QUARTZ Glass making Electronic equipment Watches Tv s/radios Most common mineral
KAOLIN China/pottery Paper Medicines Kaolin is mined in South Georgia
GYPSUM Cement Stucco
CALCITE Photography Medicines
GRAPHITE Pencils Tennis rackets
FELDSPAR Pottery Glass Porcelain
HALITE Table salt Food preservatives
FLUORITE Toothpaste Plastics
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