RHYOLITE
Rhyolite
is a felsic, extrusive igneous rock. It has the same chemistry &
mineralogy as granite, but is very finely crystalline (aphanitic texture;
crystals <1 mm in size) due to cooling of high-viscosity lava.
Rhyolites are often light gray to pinkish to somewhat reddish in color.
Rhyolite lavas are highly viscous (thick & slow-moving) when erupted and
often appear as if they have flowed like oozing toothpaste. Sometimes the
term felsite is applied to rhyolites. There does not seem to be a consistent
definition of felsite, cf. rhyolite. However, felsite appears to be the
broader term, applicable to all light-colored volcanic rocks.
Rhyolite
Rhyolite
(felsite)