2. Objectives: Describe the environments in which minerals forms Compare the two types of mining Describe two ways to reduce the effects of mining Describedifferent uses for metallic and nonmetallic minerals
3. Formation of Minerals Minerals form in a variety of environments in the Earth’s crust. Each has a different set of physical and chemical conditions that determine the minerals’ properties Evaporating Salt Water When a body of salt water dries up, minerals such as gypsum and halite are left behind
4. Metamorphic Rocks When changes in pressure, temperature, or chemical makeup alter a rock, metamorphism takes place Minerals that form in metamorphic rock include: calcite, garnet, graphite, hematite, magnetite, mica, and talc
5. Limestones Surface water and groundwater carry dissolved materials into lakes and seas, where they crystallized on the bottom Minerals that form in this environment include: calcite and dolomite limestone dolomite
6. Hot-Water Solutions Groundwater works its way downward and is heated by magma, and then reacts with minerals to form a hot liquid solution Dissolved metals and other elements crystallize out of the hot fluid to form new minerals, such as: gold, copper, sulfur, pyrite, and galena
7. Pegmatites As magma rises upward from the Earth’s crust, it can form teardrop-shaped bodies called pegmatites Many gemstones such as: topaz and tourmaline, form in pegmatites
8. Plutons As magma rises upward through the crust, it sometimes stops moving before it reaches the surface and cools slowly, forming millions of mineral crystals Eventually, the entire magma body solidifies, forming minerals such as: mica, feldspar, magnetite, and quartz
9. Mining Many kinds of rocks and minerals must be mined to extract the valuable elements they contain Geologists use the termoreto describe a mineral deposit large enough and pure enough to be mined for profit Rocks and minerals are removed from the ground by one of two methods
10. 1. Surface Mining When mineral deposits are located at or near the surface of the Earth, surface-mining methods are used to remove the minerals Types of surface mines include: open pits surface coal mines quarries
11. 2. Subsurface Mining Methods are used when mineral deposits are located too deep within the Earth to be surface mined Subsurface mining often requires that passageways be dug into the Earth to reach the ore
12. Responsible Mining Mining gives us the minerals we need, but it may also create problems Can destroy or disturb the habitats of plants and animals Waste products from a mine may get into water sources, which pollutes surface water and ground water
13. One way to reduce the potential harmful effects of mining is to return the land to its original state after the mining is completed Called reclamation Reducing our need for minerals by recycling is another way to reduce the effects of mining
14. The Use of Minerals Metallic Minerals good conductors of heat and electricity Processed for various uses Building aircraft Automobiles Communications Electronic equipment Examples of useful metallic minerals Gold Silver Copper Aluminum – frame Titanium – handlebars Beryllium – pedals Iron - spokes
15. Nonmetallic Minerals good insulators of electricity Uses range from: glass-making to producing computer chips Example: Calcite is a major component of concrete, which is used in building roads, buildings, bridges and other structures
16. Gemstones highly valued for their beauty and rarity, than for their usefulness Important gemstones include Diamond Sapphire Ruby Emerald Aquamarine Topaz tourmaline
