Download DOC ______ MINERAL NOTES Mineral

DOC ______
MINERAL NOTES
Mineral- a naturally occurring, inorganic, crystalline, solid with a definite chemical composition.
A substance is a mineral if it:
1. is solid
2. Was formed in nature (not made in a lab)
3. Is inorganic (not living)
4. Has atoms or molecules that all have the same crystal
pattern
5. Has the same chemical composition throughout
Three Ways Minerals Can Form
1. Evaporation - when water evaporates, minerals are left behind
2. Heating/cooling - magma cools and elements and compounds aggregate together to form
minerals
3. Pressure - intense pressure breaks the bonds between compounds and the atoms recombine to
form new bonds and compounds
The Earth’s Crust
Minerals come from the Earth’s crust. About 4000 minerals have been identified, but 98.5% are
made of only eight elements (silicon, oxygen, aluminum, iron, calcium, sodium, potassium, and
magnesium). 92% of all minerals in the crust contain silicon and oxygen
Question: 75% of the crust is silicon dioxide. In large pieces it is called quartz. In small pieces it is called
sand. Why would so much of the earth’s surface be covered in silicon dioxide?
Other Terminology

Rocks - mixtures of minerals

Ore - what we call rock that contains minerals that can be mined

Alloys - result when two minerals are combined (copper + zinc = brass; copper + tin= bronze)
Classification of Minerals
Some elements occur naturally but do not combine to form compounds. These are called native
elements. Some examples of these include gold, copper, and sulfur. Others form compounds and are
grouped based on what elements are present (see your Mineral Families chart!). Examples of these
families are Oxides, Halides, Sulfides, Carbonates, Sulfates, and Silicates. The Silicates is the largest
family of minerals.