Tephrite
From Wikipedia, the free encyclopedia
Tephrite is an igneous, volcanic (extrusive) rock, with aphanitic to porphyritic texture. Mineral assembly is usually abundant feldspathoids (leucite or nepheline), plagioclase, and lesser alkali feldspar. Pyroxenes (clinopyroxenes) are common accessory minerals. Quartz and olivine are absent. Occurrences include phonolite-tephrite Mt. Vulture, Basilicata, Italy, basanite–tephrite intrusions in Namibia, and leucite nepheline tephrite from Hamburg, Germany.