Are these all crystals? Why? A B DC Bell-Ringer 1 / 30

Minerals they and how they form

Geology: The study of the earth, what it is made of, and how it works

Why do we study Minerals? Minerals are the starting point for all geologic formations and activity Rocks are made of them Rocks and molten rock (lava, magma) are what shape the surface of our planet!!!

Minerals: What Are They? 1. Solid 2. Definite chemical composition Elements are in specific amounts. 3. Crystalline Has atoms that are in a repeating pattern. Pattern may be simple or complex. 4. Abiotic Naturally occurring, but not a product of any living process.

Minerals Can Be Elements or Compounds Single elements that are also minerals are called “native elements”. Most minerals are compounds made from different elements in the crust. The 8 most common elements in minerals: Oxygen (O) Silicon (Si) Aluminum (Al) Iron (Fe) Calcium (Ca) Sodium (Na) Potassium (K) Magnesium (Mg)

How Minerals Form Minerals form in 3 ways in nature: 1. The cooling and hardening of magma. 2. When water containing dissolved ions evaporates. 3. Sustained pressure, heat, or chemical action can change minerals into other minerals.

Mineral’s Crystalline Structure All minerals are crystalline. This means that all of their atoms are arranged in a repeating pattern. These can be used to identify a mineral This is because the pattern controls the way a mineral forms and breaks. There are seven crystal lattice systems in which the atoms can be arranged. This means that all of their atoms are arranged in a repeating pattern.

The 7 Crystal Lattice Systems: #1 Cubic System: 3 axes of equal length that intersect at right angles (90 ◦ ) Examples - Halite (Rock Salt) - Galena

The 7 Crystal Lattice Systems #2 Orthorhombic System: Three axes of different length that intersect at 90 degree angles. Examples: Sulfur Topaz

The 7 Crystal Lattice Systems #3 Tetragonal System: Three axes, 2 of the same length, one of different length. Examples: Wulfenite Chalcopyrite

The 7 Crystal Lattice Systems #4 Monoclinic System: Three unequal axes, two intersect at 90 degrees, the third is oblique to the other two. Example: Gypsum Borax

The 7 Crystal Lattice Systems #5 Triclinic System: Three axes of unequal length that intersect at oblique angles. Example: Turquoise Microcline

The 7 Crystal Lattice Systems #6 Hexagonal System: Three horizontal axes that are the same length, and a vertical axis that is longer than the horizontal axes. Example: Quartz Graphite

The 7 Crystal Lattice Systems #7 Rhombohedral System: Three axes that are the same length, all at oblique angles. Example: Ilmenite Dolomite Gratonite