Another one of the more mysterious and confusing stones in our library, due mostly to its close visual resemblance to Jasper. Some people consider Rhyolite “rainforest jasper”, which is not truly correct, it is a common volcanic rock, and has a very similar chemical equivalent of granite.
The difference being that while granite is intrusive, with crystal that are easy to see because the magma cools more slowly; Rhyolite is extrusive and due to the more rapid cooling of the lava the crystals are generally too small to see.
Some call the stone the “Streaming Rock” due to the colored bands, bubbles and crystal-rich layers of material that forms when the lava flows over stone surfaces and slowly moves forward. Depending on how it erupts and how this flow is cooled and layers upon stone surfaces.
So here is where things get really tricky…the slower moving magma cools larger crystals, which often become granite. The quicker moving magma cools more slowly and form smaller crystals suck as rhyolite. They are often difficult to see, but the crystals are there, sometimes surrounded by a glassy matrix. If the lava fails to form the crystals at all, it essentially becomes obsidian.
Sometimes rounded sphericules of quartz or feldspar are found in the matrix of the stone; when the stone contains numerous vesicules (or holes basically) then the rhyolite is called pumice
Rhyolite is sometimes formed in creams, pinks, yellows and reds…this type is called Wonderstone.