Definitions for "Gneiss"
A crystalline rock, consisting, like granite, of quartz, feldspar, and mica, but having these materials, especially the mica, arranged in planes, so that it breaks rather easily into coarse slabs or flags. Hornblende sometimes takes the place of the mica, and it is then called hornblendic gneiss or syenitic gneiss. Similar varieties of related rocks are also called gneiss.
A name applied to a broad group of rocks. Generally speaking gneisses are banded rocks formed during high-grade regional metamorphism
a metamorphic rock that resembles granite. "Metamorphic rock" is rock that has been changed by heat or pressure. Herbaceous: a plant that has little or no woody tissue and is instead soft and green.
Keywords:  volcano, shield
Shield Volcano