Torfajökull is special because it is Iceland's largest rhyolitic centre and contains Iceland's largest geothermal field. Most volcanic centres contain a little bit of rhyolite, usually 10%. There are only two volcanic centres that have considerably more than 10%; Kerlingarfjöll has 25%, but Torfajökull is 80% rhyolite! Consequently Torfajökull accounts for about a third of Icelandic rhyolite. It is because of the rhyolite that Torfajökull has beautiful orange mountains (see Landmannalaugar and other pages). The large geothermal field means that there are many hot streams and pools in Torfajökull. There is one that you can bathe in at Landmannalaugar. There are other places where puddles boil and there are plenty of fumaroles (sulphurous steam vents) too. This creates some very atmospheric (and occasionally smelly) scenery.