This symbol is found on old Norse stone carvings. It is often called Hrungnir's Heart, after the legendary giant of the Edaas.
It is also know as the knot of the calin, and it has been found on stone carvings with funerary motifs, possibly a symbol of the afterlife. The nine points are suggestive of the nine worlds and the nine fates of Norse mythology.
It measure 1.25 inches in diameter. Comes on a 36 inch 2.5mm black cotton cord. CAST IN LEAD FREE PEWTER in the USA.