BCS 448 – 7th grade Science
Name:___________________________________
Date: __________________
Mineral Characteristics Review
Class # ________________
Rocks are present all around us and wherever you go, you can find them in every nook and
cranny. Rocks have been around since the formation of the Earth. They can be small or big,
smooth or rough and may have different weird shapes. Minerals, on the other hand, are
homogeneous solid substances formed by geological processes. They have a specific chemical
composition, which is not so in rocks. In fact, rocks are composed of minerals along with other
substances.
Minerals can be only identified 100% as a certain mineral by x-ray analysis and chemical tests.
The x-ray analysis determines the crystal structure of the mineral and the chemical tests
determine the composition of the mineral (the chemical formula). Structure and composition
are the defining marks of a mineral. Unfortunately for the average collector, these tests require
expensive equipment, expert know-how and often destroy the specimen. Fortunately, both
structure and composition affect certain physical properties (characteristics). Color, hardness,
luster, streak, cleavage, magnetism, acid tests, and a minerals density are a few characteristics
that we can use to identify that mineral.
For a substance to be considered a mineral, it must have the following criteria:
1) Minerals are inorganic; they are not alive and they are not plants or animals. An
example of a rock that is not a mineral is coal. Coal is a substance formed from decayed
plants and animals. Therefore, coal is not considered a mineral.
2) Minerals are found in the earth or are naturally occurring substances. They are found in
dirt, rocks, and water. They are not made by man.
3) Minerals are pure substances. Some minerals like gold or silver are made of only one
element. Other minerals, like quartz and calcite, are made up of one specific compound.
4) Minerals are solid.
5) Minerals are usually crystals. There atoms are arranged in a specific order.
Questions:
1) Explain the difference between minerals and rocks.
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2) What are some characteristics that we can use to identify a mineral? What is the difference between
“streak” and “hardness”? (check your notes)
Response: ___________________________________________________________________________________________________
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3) What are the 5 criteria for a substance to be considered a mineral?
Response: ___________________________________________________________________________________________________
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4) Why are the following substances NOT considered as being a mineral?
a) Sugar: __________________________________________________________________________________________
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b) Water: __________________________________________________________________________________________
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c) Coal: __________________________________________________________________________________________
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