The mountain bog around this stone was mined for peat in the cold centuries of Iceland, perhaps as late as the 1960s, but the stone was left. It was too big to build a fence from, too small to cut into a building block, and, besides, it wouldn’t burn in a fire.
Look how the arctic willow has clung to its warmth, though, building a rich ecosystem, even while the bog it might otherwise have rimmed is still nothing more than grass and a few flowers. The bog is now a thin layer of water mining the stone. Slowly, life will return from here.
Water and stone both flow. That the tephra cone (Eldborg) and the stream (Bólulækur) are the same colour on this June day is part of the mystery.
Both are coloured by the sky, which gains its colour by heated oxygen, which, to complete the pattern, is (more or less) on fire. The skill at recognizing these correspondences are one of the ways in which poetry adds to human knowledge of the world, and maintains it. Once you have made this realization, you will harm neither stream nor mountain.