Week 3 Lecture: Minerals Flashcards
What is a mineral?
A naturally occurring, inorganic, crystalline substance with a definite chemical composition
What are 5 environments in which minerals form?
- Hydrothermal
- Igneous
- Pegmatitic
- Weathering
- Metamorphic
What are the 6 crystal systems of minerals?
- Isometric
- Tetragonal
- Orthorhombic
- Hexagonal
- Triclinic
- Monoclinic
List the four most abundant elements in the Earth’s crust
- Oxygen
- Silicon
- Aluminum
- Iron
How does electronegativity affect chemical bonding?
- Atoms with same electronegativity form covalent bonds
- Atoms with slightly different electronegativity form polar covalent bonds
- Atoms with very different electronegativity form ionic bonds
Describe the isometric crystal form and example minerals:
-Usually appears as cube or octahedron. All axes meet at 90 degrees
- Galena
- Diamond
What are some examples of hexagonal crystal form minerals?
- Quartz
- Beryl (emerald)
What are silicates?
- The most important mineral group
- Comprise of most rock-forming minerals
- Abundant due to large amounts of silicon and oxygen in Earth’s crust
What are the two types of silicate minerals?
Mafic and Felsic
Describe isolated tetrahedral silicates
- Cations serve as links b/w tetrahedra
- No sharing of oxygen
Describe single chain silicates
Adjacent tetrahedra form a chain by sharing 2 oxygens with neighbouring tetrahedra
Describe double chain silicates
Two chains can link up by sharing oxygen
Describe sheet silcates
- Each tetrahedron shares 3 oxygen with neighbours.
- Forms sheets which are loosely bonded
e.g. (mica, biotite)
Describe framework silicates
Every oxygen in each tetrahedron is shared to form 3d framework
e.g. (feldspar, quartz)
List some non-silicate minerals
- native elements
- sulphides
- oxides
- carbonates
- sulphides
