Nomeclature
A total of 1560 rock types known today (LeMaitre et al. 2004) differ in terms of colour, texture, geotectonic position of origin, as well as mineral, modal, chemical and normative compositions. Many rocks are named after type locality or region, where they were described for the first time, for instance andesite from the Andes mountain range in western part of South America, lherzolite after the Lherz massif (recently Lhers) of French Pyrenées, or liparite after Italian Island of Lipari. Many names are derived from Greek, for example phonolite – phonos (sound) and lithos (rock), aplite – haploos (simple), Latin or other word roots, for example peridotite from French name for olivine – péridot, or after persons, for example wehrlite after Wehrle who was to first to analyze this rock type. Some names have uncertain history coming from slang descriptions of miners in ancient times. For instance the term basalt, which is most likely of Egyptian origin, is ascribed to Plinius the Elder, who published this name in 77 AD in his work Naturalis Historia. Origins of some rock names are unclear, and they are ascribed to those, who used or published them for the first time. For instance the term granite appeared for the first time in works of the English botanist, physician Caesalpin in 16th century. Only 36 rock types had been known prior to 1800. Till end of 19th century, a total of 522 rocks had been described. Boom of the descriptive petrography in the first half of 20th century resulted in ca 800 rock types. The most fruitful period, from the boundary between 19th and 20th century till 30-ties of 20th century, generated most names of the classification of magmatic rocks. Whole 20th century yielded 1002 new rock types in total. Identification of new rocks is recently not as massive as in the past two centuries and modern magmatic petrology utilizes only several tens of important and significant names. The most recent classification of magmatic rocks published by LeMaitre et al. (2004) is a result of several years lasting effort of the Subcommission on the Systematics of Igneous Rocks, working within the frame of the Internal Union of Geological Sciences. Founder and long-standing head of the Subcommission was the Swiss geologist Albert Streckeisen (1901-1998). The updated classification summarizes changes of the previous one (LeMaitre et al. 1989) and yields a complete overview of all names of magmatic rocks, including their brief characteristics and historical background of discovery.
References:
Le Maitre, R.W. (Ed), Bateman, P., Dudek, A., Keller, J., Lameyre, J., Le Bas, M.J., Sabine, P.A., Schmid, R., Sørensen, H., Streckeisen, A., Woolley, A.R. & Zanettin, B. (1989): A Classification of Igneou Rocks and Glossary of Terms. Recommendations of the International Union of Geological Sciences. Subcommision on the Systematics of Igneous Rocks. Blackwell Scientific Publications. 193 pp.
Le Maitre R. W. (Ed.), Streckeisen, A., Zanettin, B., Le Bas, M. J., Bonin, B., Bateman, P., Bellieni, G., Dudek, A., Efremova, S., Keller, J., Lameyre, Sabine, P. A., Schmid, R., Sørensen, H. & Wooley, A. R. (2004): Igneous Rocks: A Classification and Glossary of Terms. Recommendationas of the International Union of Geological Sciences. Subcommision on the Systematics of Igneous Rocks. Cambridge University Press. 236 pp.