I.) Optical Mineralogy

Understanding the following concepts is essential to mineral identification in thin section.

During the test you will be asked to identify minerals in thin section. You will also be asked specific questions regarding the optical properties of this mineral that will require you to know these concepts.

Isotropic and Anisotropic: You should be able to identify whether or not a mineral is isotropic or anisotropic.

Uniaxial and Biaxial: You should be able to identify whether or not a mineral is uniaxial or biaxial. You should also be able to distinguish a uniaxial figure from a biaxial figure, however you will not be asked to determine the optic sign. You will be asked to estimate the 2V angle.

Extinction: You should be able to determine whether a mineral exhibits Parallel, Symmetrical, or Inclined extinction.

Pleochroism and Birefringence: You should know the difference between pleochroism and birefringence. Estimating birefringence.

Relief: You should understand relief and be able to estimate if a mineral has high, moderate, or low relief.

II.) Rock Classification

Intelligent communication between geologist begins with a working knowledge of rock classification.

Rock classification requires mineral identification, estimation of modal proportions, and recognition of rock textures. You will be asked to identify the major minerals present in hand sample and classify the rock according to the IUGS Classification Scheme. You will also be asked to describe the textures of rocks using appropriate geologic terms. This will also include terms that describe textures in cumulate rocks.

You should be able to distinguish between I-, S-, and A-type granites.

III.) Minerals you should know and love:

Olivine, orthopyroxene, clinopyroxene, amphibole (hornblende, riebeckite), biotite, plagioclase, alkali-feldspar, quartz, zircon, apatite, epidote, allanite, cordierite, muscovite, garnet, spinel, tourmaline, titanite (sphene), fluorite, opaques,

Alteration; serpentine, sericite, pinnite, calcite, zoisite, chlorite.