The Swastika or Fylfot as we call this symbol in the Germanic North is also known as Thor`s Hammer and a very stylised depiction of this sacred symbol was used in Iceland for magical purposes.
The symbol was pictured on page 301 in Sabine Baring-Gould`s Iceland. Its Scenes and Sagas along with other Galdr Staves, special magical symbols, often referred to as runes but technically they are not. They were used purely for magical purposes and as far as I am aware their presence has not been detected outside of Iceland. An example of this sign used as a spell is contained in the Huld Manuscript which was added as an appendix to The Galdrabok. An Icelandic Book of Magic by Stephen Edred Flowers, Ph.D[aka Edred Thorsson]. The Thor`s Hammer/Fylfot is shown superimposed over the side profile of a man`s head.
Above the image the manuscript states:
"This sign is used by magicians to call out thieves and other witcheries."
In the notes section of the book Dr Flowers states:
"This is a most unusual Thors hammer. It may be a depiction of how the hammer is supposed to work."Dr Flowers emphasises the importance of Thor`s role in Icelandic magic:
"Perhaps the second most actively represented of the old gods is Thor. This is not surprising either, since he seems to have been the most popular god in pagan Iceland. In the Galdrabok his actual name is not represented outside the litanies of divine and demonic names in spells 43, 45 and 46. However, there is other evidence to show that Thor`s role in Icelandic magic was significant through a galdrastafur called thorshamar [Thor`s hammer]. The name of this sign was attached to several forms over a long history. At one time it was attached to the solar wheel, or swastika, and is recorded in the folklore material of Jon Arnason [here the symbol is shown-my edit], which seems reminiscent of the old solar wheel.[Flowers]
It may be significant that the upper arm of this Thor`s Hammer resembles specifically the hammer form whilst the rest takes more of the Fylfot shape.