In order to make the glossary a standard reference for the future, every effort has been made to make the list of rock names as complete as possible. The initial list included all the names found in standard reference texts and glossaries such as Johannsen (1931, 1932, 1937, 1938, 1939), Tröger (1935, 1938), Sørensen (1974) and Tomkeieff et al. (1983), except for varietal names as outlined in section 3.1.1. This list was later extensively edited and modified by suggestions from contributors and particularly when the references were checked. The list published in the 1st edition contained 1586 terms which has now been extended to 1637.

DETAILS OF ENTRIES

Most of the glossary entries consist of five types of information:

1. the term, with any alternative spellings in brackets

2. a brief petrological description or comments on the term

3. the author(s), year and page number of the source reference

4. the origin of the term

5. the location of the term in three standard texts.

Where given the last three are printed in italics and enclosed in brackets. Each of these five types of information is described in further detail below.

CHOICE OF TERMS

The principles with which names have been included in the glossary have been somewhat subjective. In general, varietal names have not been included where they are self-explanatory, e.g. hornblende granite, biotite granite.