Unit 4 – Earth’s Minerals
HS-ESS3-2. Evaluate competing design solutions for developing, managing, and utilizing energy and mineral
resources based on cost-benefit ratios.
HS-ESS3-6. Use a computational representation to illustrate the relationships among Earth systems and how those
relationships are being modified due to human activity.
Mineral Characteristics
1. A mineral is defined as a naturally occurring, inorganic, solid, definite chemical
composition (chemical formula), an orderly arrangement of atoms.
2. The most abundant elements in the Earth’s crust are oxygen (46%), silicon (28%), aluminum
(8%), iron (5%), calcium, sodium, potassium and magnesium (2-3%).
3. Most minerals are made of compounds, and a few are made of single elements such as the
native elements copper, gold, sulfur, silver and diamond.
4. Rocks are composed of a mixture of mineral compounds and native elements in varying
amounts.
5. There are over 4000 minerals, but only about 30 common ones that make up most of the
Earth’s crust. These are called rock-forming minerals.
Mineral Properties
6. Minerals can be distinguished and identified by their physical and chemical properties.
7. The way that a mineral reflects light is called luster, and it can be described as metallic, dull,
earthy, vitreous (glassy), pearly, or adamantine.
8. The color of the powdered mineral is its streak. The same mineral can exhibit different
colors, but will have the same streak color. Ex. Hematite.
9. The Mohs scale can determine the relative hardness of a mineral on a scale from softest 1
(talc) to the hardest 10 (diamond).
10. The hardness and density of a mineral depends on the crystalline arrangement of its atoms.
Ex. Diamond and graphite.
11. The specific gravity of a mineral is a ratio that compares how many times more dense the
mineral is compared to water.
12. The mineral calcite (calcium carbonate CaCO3) chemically reacts to hydrochloric acid by
“fizzing” (releasing carbon dioxide gas). Objects viewed through transparent calcite will appear
“double”.
13. Other minerals are magnetic or radioactive.
Crystal Formation
14. Minerals forms in three ways; cooling of magma, by heat and pressure or by evaporation.
15. A crystal is defined as a geometric solid that has a regular, orderly arrangement of atoms. A
crystal has smooth surface faces.
16. Large well-formed crystal size is determined by more time, space, pressure, concentration
and by lower temperature.
17. The crystal structure determines of a mineral will cleave or split along weak bonds between
definite planes. Halite cleaves at 90º angles while quartz does not cleave, but only fractures.
18. Mica has perfect (flat) cleavage due to weak bonds between layers of atoms.
19. Graphite and diamond are the different arrangement of the same carbon atoms: graphite in
weakly bonded layers and diamond in a strongly bonded 3 dimensional structure
Mineral Groups
20. Silicates are minerals that contain silicon, oxygen and they make up 90% of all minerals in
the Earth’s crust.
21. Silicates are composed of a silicon-oxygen tetrahedron which is a molecule of one silicon
atom combined with 4 oxygen atoms. It is an ion with a negative charge which enables it to
combine with positive metallic ions to forms many different minerals.
22. Other mineral groups include carbonates, oxides, sulfides, sulfates.
Mineral Resources
23. Renewable Resources: one that can be replaced in nature at a rate close to its rate of use
24. Nonrenewable Resources: exists in a fixed amount or is used up faster than it can be
replaced in nature (MINERALS) *recall that Earth is a CLOSED system
25. A mineral ore is rock that contains enough of a metallic element to make separation
profitable is called an ore; ore mineral is the valuable mineral (metal) that can be separated.
Examples: iron ore, copper ore
26. Mineral Resources are estimates of minerals that are available globally. And a mineral
Reserve is the mineral in ores that are worth mining.
27. Surface Mining changes the land by removing tons of soil, ore or rock which often creates a
rocky waste that supports little life; often what is left- barren hills, level mountains, dangerous
collections of water/run off, pollutants
28. Purposes of Conservation: protection, restoration and management of natural resources.
29. EPA: Environmental Protection Agency-monitors and sets standards for drinking water and
air quality.