Rhyolite rock is quite rare.
It is an extrusive
which is formed when extremely explosive volcanoes erupt.
Its lava is
so viscous, sticky and so much lacks volatiles, that it piles up and
builds lava domes instead
of flowing away when it does reach ground.
It often has
(large crystals) that formed underground, in intrusive
conditions, and a fine-grained matrix that formed from lava once the
volcano had erupted.
Rhylote rock by JesÃƒºs RodrÃƒguez
It can also have a banded texture which lacks
Common minerals are quartz, feldspar, pyroxene, amphibole
If a magma with the same composition would be formed
completely underground, this rock would be granite.