A mineral may be defined as any naturally occurring chemical element or compound formed as a product of inorganic processes. This eliminates all artificial products of the laboratory as well as all natural products formed by organic agencies. The above definition is brief; and, though it embraces most of the substances considered as minerals in this book, it should be considerably expanded to be all-inclusive.

Minerals are the materials of which most of the rocks of the earth's crust consist and are, therefore, among the common objects of daily observation. The great majority of rocks are not made up of single minerals, but are more or less heterogeneous aggregates of several different species. A few rocks, like limestone and quartzite, consist of but one mineral in a more or less pure state. In addition to occurring as essential and integral parts of rocks, minerals are found distributed through them in a scattered way, or in veins and cavities. <...>

In this, the first attempt to give in English a comprehensive review of petrographic methods, it cannot be otherwise than that there should be many omissions—it is to be hoped not many errors. If any is found the author will be extremely glad to have his attention called to it, as he will also be for criticisms, or suggestions for additional material that should be included.

This book is the third in a series of three, intended primarily to provide a working manual for laboratory technicians and others engaged in the testing of soils for building and engineering purposes. It is not meant in any way to be used as a substitute for the Standards referred to therein, but to augment their requirements by the provision of step by step procedures. This third edition has been revised to take account of the current requirements of BS 1377: 1990,

THREE A S TM STANDARDS are available for sampling coal: ASTM Practice for Collection of Channel Samples of Coal in the Mine (D 4596), ASTM Test Methods for Collection of a Gross Sample of Coal (D 2234), and ASTM Practice for Collection of Coal Samples from Core (D 5192). The first two standards are applicable only to existing mining operations, test pits, or transportation of coal.