JLKR+4.3

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Vocabulary

 * gemstone-** a stone that is a colorful and hard mineral that has a glassy or brilliant luster
 * ore-** a rock that has metals in it or economically useful minerals
 * alloy-** a solid mixture of two or more metals that are combined

The Uses of Minerals

 * minerals can be used to make metals, gemstones, and other materials used to make many products
 * gemstones
 * people value gemstones for their luster, color, and durability
 * some are very expensive
 * once a gemstone has been properly cut and polished, it is then called a gem
 * gems are mostly used for jewelry and decoration
 * metals
 * metals are very useful
 * they can be stretched into wire, flattened into sheets, and they are pretty flexible
 * other useful minerals
 * some uses of minerals
 * talc can be used for talcum powder
 * fluorite is important for making aluminum and steel
 * clear calcite are used in optical instruments such as microscopes

Ores

 * most metals don't occur in a pure form
 * much of the world's copper comes from ores containing the mineral chalcopyrite

Prospecting

 * a prospector is someone who prospects for ore deposits
 * geologists prospect for ores by looking at certain features on the earth's surface
 * they observe the kinds of rocks on the land
 * they examine the plants that are growing
 * they test stream water for the presence of certain chemicals

Mining

 * there are three types of mines
 * strip mines
 * earthmoving equipment scrapes away the soil to expose ores
 * shaft mines
 * shaft mines usually have a network of tunnels that extend deep into the ground, following the veins of ore
 * open pit mines
 * miners use giant earthmoving equipment to dig huge pits

Smelting

 * after miners remove ore from a mine, they have to smelt it to remove the metals from the ore
 * heat causes the metals to separate from the oxygen with which it is combined