Minerals Properties and Uses A Mineral is Naturally

Minerals: Properties and Uses

A Mineral is Naturally occurring n Inorganic (not made from animals or plants) n Solid n with a definite chemical composition (formula) n and an orderly arrangement of atoms (crystal structure) n

Crystal Structure

What determines the use or uses of a particular mineral? Use is determined by n physical properties n chemical composition n

What are physical properties? Color n Luster n – Metallic – Nonmetallic n Streak – Color of the powdered mineral n Hardness – Moh’s Scale from 1 -10 n Breakage – Cleavage – Fracture

Physical Properties Unique combinations for each mineral n Useful for Identification n Determine some uses n

Use determined by physical properties Chemical composition is of little concern. n Specific physical properties are the basis for use. n Examples: n – Quartz for its hardness: sand paper – Talc for its absorbency: baby powder – Graphite for its softness: pencil “leads” – Halite for its taste

Graphite

Talc

Some minerals are used for their chemical composition Physical properties are of little concern n Chemical composition is important because certain minerals are sources of valuable chemical elements or are of use by themselves. n

Examples of minerals used for their chemical composition n Gold – jewelry, dentistry, electronics

Examples of minerals used for their chemical composition n Hematite, magnetite, limonite – iron and steel

Examples of minerals used for their chemical composition n Malachite, azurite, chrysocolla – copper: wires, pennies, electronics

Examples of minerals used for their chemical composition Gold – jewelry, dentistry, electronics n Hematite, magnetite, limonite – iron and steel n Malachite, azurite, chrysocolla – copper: wires, pennies, electronics n Galena – lead, formerly plumbing and paints, now – mostly chemicals industry n Bauxite – aluminum: cans, foil, bikes, aircraft, etc. n

Abundance of chemical elements in Earth’s Crust O – 46. 6% n Al – 8. 1% n Ca – 3. 6% n K – 2. 6% n Other – 1. 7% n Si – 27. 7% Fe – 5. 0% Na – 2. 8% Mg – 2. 1%

Other Chemical Elements 1. 7% of crust n Highly useful n Highly valuable n Example: Copper – average crustal abundance is 50 ppm, but the US alone uses 2 million tons per year! n