ore. So, the ore must be separated from unwanted rocks. Then, the minerals need to be
separated out of the ore. The work is still not done once the mineral is separated from the
unwanted materials (Figure3.30).
Most minerals are not pure metals, but chemical compounds that contain metals and other
elements. The minerals must go through chemical reactions to make pure metals. In order
for the reactions to happen, chemicals must be added to ores that have been melted. High
temperatures are needed to melt ores. Think about the ways you use aluminum foil in your
home. It is put into hot ovens and over flames on a grill, but it does not melt. Making
aluminum requires a lot of energy. Temperatures greater than 900oC are needed to make
pure aluminum. Then, a huge amount of electricity is needed to separate the aluminum from
other elements to produce pure aluminum. If you recycle just 40 aluminum cans, you will
save the energy in one gallon of gasoline. We use over 80 billion cans each year. If all of
these cans were recycled, we would save the energy in 2 billion gallons of gasoline!
Figure 3.30: When the water in glass A evaporates, the dissolved mineral particles are left
behind. ( 19 )
Gemstones and Their Uses
Some minerals are valuable because they are beautiful. Jade has been used for thousands of
years in China. Native Americans have been decorating items with turquoise since ancient
times. Minerals like jade, turquoise, diamonds, and emeralds are gemstones. Agemstone,
or gem, is a material that is cut and polished to use in jewelry. Many gemstones, such as
those shown in theFigure3.31, are minerals.