Missourians are interested in the rocks and minerals which they find on
their farms, in excavations, and while on their vacation trips. Some of
the specimens are unusual in shape or appearance, some are crystalline
and beautiful, some may be ores of economic importance, but many simply
arouse the curiosity of the finder.
Many of these specimens are received each year at the University at
Columbia, and each is usually accompanied by a request for information
on the correct name for the specimen, its composition, its commercial
value, and the manner of its formation.
Frequently the requests include questions of a broader geological
nature, or seek the recommendation of a general, easily-read book
written on rocks and minerals which may be purchased at a book store or
consulted at a library. Moreover, many persons ask how they may
determine for themselves the geological specimens which they have
collected.
This little booklet has been prepared with the intention of answering
the questions most commonly asked by citizens of the state about
Missouri rocks and minerals.
Descriptions and photographs of Missouri rock and mineral occurrences
are provided, and essential facts about the geological conditions of
their formation are simply told. A determinative key is supplied in
order that the reader may identify and name most of the common specimens
which he collects within the state (and elsewhere, also). No special
determinative equipment will be suggested, and only non-technical
language will be employed because the chief objective here is to furnish
a useful, understandable geological account of the _common_ Missouri
rocks and minerals to the average person without geological training. In
fact, for the purposes of identification no differentiation is made
between mineral and rock, although the professional geologist does
separate them in definition. For our purpose, a rock is an aggregate of
mineral particles, but a mineral is a substance (without life) having
more definite and constant properties than a rock. For those interested
further, more technical and more nearly correct definitions, with
explanations, are given at the back, on page 74.
The rarer minerals and those requiring special equipment for
determination may be sent to the Department of Geology of the University
of Missouri at Columbia for identification free of charge.[1]
Names used locally, and sometimes incorrectly from a strictly technical
sense, for rocks and minerals will follow the generally accepted names,
and both will be duplicated in the index at the back of the pamphlet to
facilitate finding either one.