Introduction to Mineralogy

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Mineralogy

Introduction to Mineralogy

Elements of Mineralogy

1) Crystallography:

Symmetry, external morphology, and internal structure.

2) Chemistry of minerals:

Interpretation of chemical analyses, crystal chemistry (including bonding of atoms, sizes of ions, solid solution, etc.).

3) Physics of minerals:

Density, hardness, cleavage, optical, magnetic, radioactive, and electrical properties.

4) Mineral genesis:

Phase relations, igneous, metamorphic, & sedimentary environments.

5) Determinative mineralogy:

Diagnostic properties of a physical nature and chemical tests.

6) Classification of minerals:

i.e. - Descriptive mineralogy.

Definitions:

Mineral:

A naturally occurring solid inorganic substance which has fixed limits of chemical composition.

A homogeneous solid with an orderly internal atomic arrangement.

Klein and Hurlbut (Manual of Mineralogy) give the definition as:

A naturally occurring homogeneous solid with a definite, not fixed, chemical composition with an ordered atomic arrangement formed by inorganic processes.

Homogeneous solid = mechanically seperable from its surroundings.

Definite chemical composition:

determinable, definable extremes

solid solution:

ability of ions/atoms to mutually substitute for each other

example:

magnesite (MgCO3) - siderite (FeCO3)

never really pure - usually a mixture of Mg and Fe (Mg,Fe)CO3

this is a DEFINITE, but not FIXED chemical composition.

Finally, things like coal and petroleum are not minerals, they are organic and do not have definite chemical compositions.