This page provides a brief outline of, lists the main points of, gives links to figures for, and lists the assigned reading for a lecture in Dr. Bruce Railsback's GEOL 1121 class at the University of Georgia. This page is not intended as a set of lecture notes, and it cannot subsititute for a set of lecture notes. Familiarity with this page alone will not assure satisfactory grades on exams in the course.

Lecture 5 (Wednesday, January 16): Silicate Minerals

Brief outline of this lecture:
The silica tetrahedron
General silicate structures
Silicate minerals - a general list
Major silicate minerals in igneous rocks

Main points of this lecture:
All silicate minerals consist in some way of Silicon ions surrounded by four oxygens ions, or by silica tetrahedra.
Silica tetrahedra can exist in minerals alone, in pairs, in single chains, in double chains, in sheets, and in three-dimensional frameworks.
The shape and cleavage of many silicate minerals depend on whether they consist of chains, sheets, or 3D-frameworks of silica tetrahedra.
Many properties of silicate minerals vary in a continuum from the most mafic (olivine) to the most sialic (quartz).

Figures used in this lecture:
The silica tetrahedron
Silicate mineral structures I
Silicate mineral structures II - top of diagram
Silicate mineral structures II - bottom of diagram
Silicate mineral structures III
A list of silicate minerals
Silicate minerals in igneous rocks

Reading assignment: Pages 31-32.

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