A Dryad is a tree nymph, a female spirit of a tree, in Greek mythology. In Greek drys signifies "oak". Thus, dryads are specifically the nymphs of oak trees, though the term has come to be used for all tree nymphs in general. They were normally very shy, except around the goddess Artemis, who was known to be a friend to most nymphs.
East of Reykjavik, Iceland lies the mountain, Hengill. Hengill was formed from a Palagomite tuff, it is a central volcano and has a giant magma chamber beneath it. When thick basalt lava flows cool, they form hexagonal cracks, called columnar joints. These can be found also in Ireland & Scotland.