PHONOLITES-Phonolite-English

*Who we are*
*Conductor*
*Singers*
*Coordinator*
*Repertoire*
*Concerts*
*Rehearsals*
*Links*
*Contact us*
*Our news*
*Phonolite*

Phonolite

Phonolite is a volcanic rock. It was originally "Klingstein" in German on account of the sound emitted when it was struck by a hammer. It consists mainly of nepheline and alkali feldspar (sanidine or anorthoclase). Other minerals occuring in phonolite are soda-pyroxenes, soda-amphiboles, leucite, analcime and sodalite-group minerals (sodalite, nosean, hauyne). It is the volcanic equivalent of nepheline syenite.

Phonolite in hand specimen
			Phonolite is grey to dark green, usually with a porpyritic texture and a greasy lustre due to the presence of nepheline, which is also called elaeolite. Left: phonolite, Right: leucitophyre

Phonolite under the polarizing microscope
Nicols //	Nicols X	Phonolite Sa: sanidine, Ne: nepheline Marangudzi, Zimbabwe
		Phonolite Ne: nepheline Comoro Islands, Indian Ocean
		Leucite phonolite Lct: leucite, Ne: nepheline Eifel, Germany
		Nosean leucite phonolite Lct: leucite, Nsn: nosean Laacher See, Germany

Pictures are taken from:
The Hamlyn Guide to Minerals, Rocks and Fossils (W.R. Hamilton, A.R. Wooley and A.C. Bishop)
Atlas of Igneous Rocks and their Textures (W.S. MacKenzie, C.H. Donaldson and C. Guilford)
A Colour Atlas of Rocks and Minerals in Thin Section (W.S. MacKenzie and A.E. Adams)