Hrafntinnuhryggur (The Obsidian Ridge; 685 m) is a rhyolite ridge with a large obsidian dyke through it entire length just east and southeast of Mt Krafla in the Myvatnsoraefi Area.  It most probably was created during a sub-glacial eruption.  Pieces of differently large obsidian lie scattered in the screes and people have to be extremely careful about their eyes, if the try to break the glassy stones into smaller pieces, because splinter tend the fly in all directions.

An easy walk from the explosion crater Viti in the slope of Mt Krafla, up the mountain and down its southeastern, up the obsidian ridge and down the valley leading to the geothermal power station is to be recommended.  If people wish to drive up to the obsidian ridge, they have to ask for permission at the power station, because the road is closed with a chain.