Traditional scandinavian (vickings) amulet are made of steel, entirely by hand, the techniques of hot forging.
In Scandinavian tradition the hammer of Mjollnir (other-Skand. "The executioner") is a tool and weapon of Thor, symbolized the destruction of the obstacles and achieving the goal. Amulets in the form of a hammer, people wore them on the neck. Also they were used in sacred ceremonies they blessed the wedding. They were put under the bed of newlyweds to have many children. A lot of pendants and amulets in the form of a hammer or a stylized image found by archaeologists testify to the large distribution of this talisman.
Please note, that since it's all handmade sizes and shapes may slightly vary.