Minerals
Have you ever thrown a rock? Ever
seen a diamond ring? Ever added salt to your food? If you have, then you’ve had
a close encounter with minerals.
WHAT’S A MINERAL?
Minerals come mainly from rocks. To
be considered a real mineral, a substance has to occur naturally and it has to
come from inorganic material. Inorganic means not created by living things. Oil
and coal, for example, come from the remains of ancient plants. So they’re not
considered real minerals, at least by scientists.
But water is! It’s one of only two
minerals that naturally occur as a liquid. (The other is the liquid metal
mercury.) Think about that the next time you drink a glass of water: You’re
drinking a mineral!
MINERALOGY
The study of minerals is called
mineralogy. Scientists called mineralogists identify and name minerals. They
figure out how minerals form. They examine mineral structure and study mineral
properties. These properties include how hard the mineral is, how it reflects
light, how it breaks, and how it reacts to chemicals.
Mineralogists also determine the
structure and content of a mineral. Most minerals are combinations of different
chemical elements. Table salt, for example, is a combination of the elements
sodium and chlorine. Some minerals can come in pure form, like with a pure gold
nugget.
USES OF MINERALS
There are thousands of types of
known minerals. They are used for all kinds of things.
All metals are minerals. So
anything made using metal is made using minerals. Anything made from clay, such
as a ceramic mug, is made from minerals. Minerals called silicates are used to
make glass. Granite, limestone, and other hard minerals are used as building
materials. Colorful minerals can be ground up and used in dyes. Minerals were
even used to make parts of the computer you’re working on!
MINING
Useful minerals aren’t normally
found just lying around. They have to be dug from the ground and separated from
other minerals.
Taking a mineral from the ground is
called mining. Usually, the desired mineral is mixed with other minerals
underground. Miners first have to dig up lots of rocks that contain several
different minerals. The mineral being mined is then separated out, or extracted,
from the others in the rocks.
Sometimes the desired part of the
mineral has to be purified even further. Iron, for example, often occurs in a
mineral called hematite. Hematite is made of iron combined with oxygen. Once the
hematite has been mined and separated from other minerals the iron has to be
separated from the oxygen.
Through much of history, the search
for minerals has attracted explorers. Mineral resources have brought about the
development of regions and have brought wealth to countries rich in
minerals.
PRECIOUS MINERALS
Some minerals are considered
particularly precious. They are valuable because they are rare and beautiful.
Gold and silver are good examples. Both are valuable and beautiful metals, but
because gold is harder to find, it’s more valuable.
Other precious minerals are called
gemstones, or gems. Gems are mainly used in jewelry but are also valued for
their hardness. People value gems like emeralds and rubies for their color. Gems
are also valued for their luster. Luster is the way the gem reflects light.
Diamonds are the most lustrous of
minerals. They are a favorite for jewelry. But diamonds are also the hardest of
all minerals. So they are used for things that require a very hard material. The
drill used by your dentist probably has diamonds on it. A saw with diamond teeth
can cut through steel!
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