In Norse mythology the Viking God Odin’s eldest son was Thor. He protected the universe with his mighty hammer Mjölnir. He is the god associated with thunder. While it is generally recognized and depicted as a hammer, Mjölnir is sometimes referred to as an axe or club.
Mjolnir is also linked to luck, prosperity, power, and protection in Nordic rituals
This is fairly small so would also work well as an earing.