SCORIA
Scoria
is a frothy-textured, mafic extrusive igneous rock. It has an abundance of small holes formed by
trapped gas bubbles during solidification of volcanic lava. The solid
portions of scoria can be glassy or finely crystalline (aphanitic). If a
scoria's solid portions are not glassy, the material typically has the same
mineralogy as basalt. Another term for many scorias would be scoriaceous
basalt. Some scorias are intermediate in chemistry (but still dark in
color), and are better named scoriaceous andesites.
Fresh scoria is typically black to dark gray in
color. Weathered/oxidized samples tend to be brownish and reddish in
color. Most scorias are a bit too dense to float in water, but there are
exceptions.
Scorias are relatively common landscaping rocks around
many restaurants and businesses.
Scoria
Scoria
Scoria