Introduction to Minerals Created By: Mr. Kreeger

Homework and Page References HW # 1- 8-12 on page 37 of text HW # 2- 13-15 on page 41 of text HW # 3- Explain what gives minerals their external features and how does their atomic structure affect this?

Table of Contents Minerals Defined Characteristics of Minerals Mineraloids Industrial Minerals Biochemical Minerals Characteristics of Minerals Crust Composition Examples of Various Mineral Compositions Crystalline Form

Introduction to Minerals

1. Minerals Defined A mineral is the basic material that makes up the earth’s crust and has the following characteristics: Naturally occurring Inorganic Has a fixed chemical composition Has an orderly internal arrangement of atoms.

1. Minerals Mineraloids-Lack crystal structure (Examples include rare gemstones) Industrial Minerals- Used for manufacture of physical materials. Biochemical Minerals- Can be manufactured by organisms (Example: Aragonite-Made by clams to produce their shells)

2. Characteristics of Minerals Naturally Occurring- Formed as a result of natural processes in or on the earth Inorganic- Came from things that were never alive. Fixed Chemical Composition- Use of a chemical formula or symbol to represent what mineral is made of. 1. Some minerals found as pure elements (Cu, Ag), most are found as compounds (Calcite(CaCO3), Quartz(SiO2).

3. Composition of Crust **98% of the crust is made of just 8 elements, even though there are over 100 known elements ( Pg 11 of ESRT) Element % by Mass Oxygen 46.40 Silicon 28.15 Aluminum 8.23 Iron 5.63 Calcium 4.15 Sodium 2.36 Magnesium 2.33 Potassium 2.09 Nitrogen Hydrogen Other 0.66

Composition of Crust

4. Examples of Various Mineral Compositions Chemical Name Chemical Formula Calcite Calcium Carbonate CaCO3 Galena Lead Sulfide PbS Gypsum Calcium Sulfate-Water CaSO2 +2H2O Olivine Magnesium Silicate Mg2SiO4 K-Feldspar Potassium aluminum silicate KAlSi3O8 Pyrite Iron Sulfide FeS2 Quartz Silicon dioxide SiO2

Pictures of Minerals

Uses of Minerals

5. Crystalline Form Atoms or molecules of a mineral are the same throughout that mineral There is a definite repeating pattern in minerals, if pattern is large enough to be seen it is called a crystal. Internal structure determines outside structure.

5. Crystalline Form Isometric- 3 axis of equal length, intersect at 90 degrees (Galena, Halite, Pyrite) Orthohombic-3 axis of different length, intersect at 90 degrees (Olivine, topaz)

5. Crystalline Form Triclinic- 3 axis of unequal length that are oblique to one another (Plagioclase Feldspar) Monoclinic- 3 axis of unequal length, 2 intersect at 90 degree angles, the other is oblique to others (Mica, Gypsum)

5. Crystalline Form Hexagonal- 3 horizontal axes of same length intersect at 60 degree angles. Vertical axis can either be longer or shorter than horizontal axis. (Calcite) Tetragonal- 3 axes intersect at 90 degree angles. Two horizontal axes are equal length. Vertical axes is longer or shorter than horizontal axes. (Cassiterite)

crystal shape The shape of the mineral’s crystals as a result of its atomic arrangement