Rhyolite is an extrusive igneous rock, formed from magma rich in silica that is extruded from a volcanic vent to cool quickly on the surface rather than slowly in the subsurface. It is generally striated in color and it is typically very fine-grained. Always use a mask when carving this stone. It is a medium hardness and holds detail well. The beautiful coloration can come in swirls or circles.
