Minerals

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Slide 32

Cleavage

Tendency to split along smooth planes of weaknessbetween atoms in crystal

Directly related to atomic structure

Related to Crystal Form

Every cleavage face is a possible crystal face

Not every crystal face is a cleavage face. Quartz commonly forms crystals but lacks cleavage.

4. Minerals can be identified by their physical properties = atomic structure

Slide 33

Other Properties

Crystal Form

Takes Luck & Practice

Well-formed crystals are uncommon

Crystal Classification is somewhat subtle

Fracture

4. Minerals can be identified by their physical properties = atomic structure

Slide 34

Identifying Minerals

Geologic Setting

Some minerals occur in all geologic settings: quartz, feldspar, pyrite

Some minerals occur mostly in sedimentary settings: calcite, dolomite

Some minerals occur mostly in igneous settings: olivine

Some minerals occur mostly in metamorphic settings: garnet, kyanite

4. Minerals can be identified by their physical properties = atomic structure

Slide 35

Identifying Minerals

Special Properties

Taste, Magnetism, Etc.

Experience and Reading

“The best geologist is the one who’s seen the most rocks.”

Professional Methods

Chemical Analysis

X-Ray Studies

Thin Section

4. Minerals can be identified by their physical properties = atomic structure

Slide 36

Diffraction

4. Minerals can be identified by their physical properties = atomic structure

Slide 37

Diffraction

4. Minerals can be identified by their physical properties = atomic structure

Slide 38

A Common Example

Slide 39

Diffraction in Opal

4. Minerals can be identified by their physical properties = atomic structure

Slide 40

MAJOR MINERAL SUITES

Elements

Metallic:Au, Ag, Cu

Not Al, Pb, Zn, Fe, etc.

Nonmetallic: C - Diamond, Graphite

Sulfur

4. Minerals can be identified by their physical properties = atomic structure

Slide 41

Copper Nugget

Slide 42