Tephrite

Not to be confused with tephroite.

Tephrite is an igneous, volcanic (extrusive) rock, with aphanitic to porphyritic texture. Mineral content is usually abundant feldspathoids (leucite or nepheline), plagioclase, and lesser alkali feldspar. Pyroxenes (clinopyroxenes) are common accessory minerals. Quartz and olivine are absent. The absence of olivine distinguishes them from the otherwise similar basanite. It's parameters are defined in the QAPF diagram. Occurrences include leucite nepheline tephrite from Hamberg bei Neckarelz near Heidelberg, Germany,^[1] phonolite-tephrite at Monte Vulture, Basilicata, Italy and basanite–tephrite intrusions in Namibia.

Leucite tephrite from Mayen, Eifel, Germany

References

1. Frenzel, Gerhard (1953). "Die Erzparagenese des Katzenbuckels im Odenwald". Contributions to Mineralogy and Petrology (in German). 3 (6): 409–444. doi:10.1007/BF01129196.. Retrieved 2012-04-11.