composition and structure of minerals after completing this section, students will discover the...
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Composition and Structure of Minerals
After completing this section, students will discover the unique physical characteristics of various
minerals (Standard PI – 021)
All the rocks of the Earth’s crust consist of minerals
A mineral has the following characteristics
Minerals occur naturally
Minerals are found in the ground, or in water. Halite is formed from dissolved
seawater
Minerals are solid
Many minerals are formed from solidified magma
Minerals have a definite chemical composition
Sodium chloride is the chemical formula for halite
The have atoms arranged in an orderly pattern (form crystals)
There are 6 families of crystal families
Minerals are inorganic (never alive)
There are over 4000 known minerals. But 8 minerals make up
98% of the earth’s crust
More than 90% of the minerals in the earth’s crust are compounds containing oxygen and
silicon
Most minerals are compounds. A compound is a combination of
two or more elements
A few minerals consist of single elements and are called native
elements
Native gold
Minerals can form in many ways. Some form from molten rock
(magma)
As the magma cools, the atoms, ions and molecules move closer together and form chemical bonds that create compounds
These are examples of minerals that form from magma
tourmaline
basalt
plagioclase
Some minerals from as water containing dissolved ions slowly
evaporates.
Sylvite forms from sodium and chlorine ions dissolved in water
Still other minerals form from heat, pressure or chemical
action
Copper ore formed from pressurization