n. An igneous, volcanic rock with a high iron content.
The Century Dictionary and Cyclopedia
n. A name first used by Fr. Von Hauer and Stache, in 1863, in describing the geology of Transylvania, to include the varieties of greenstone-trachyte which contain quartz.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a grey volcanic rock containing plagioclase and quartz and other crystalline minerals
Word Usage
"Basalt magma typically generates very little ash compared to other types (andesite, dacite, and rhyolite)."