The VA will provide a headstone for any eligible veteran, even if they're already in an unmarked grave, in any cemetery around the world. In selecting a headstone, the National Cemeteries Administration has approved only 66 possibilities to date — which includes the Hammer of Thor for any believers of Norse gods out there.
Mjölnir (Thor's Hammer) was one of two selected in 2013. The other was an icon of a sandhill crane for a same-sex spouse of a departed veteran.
Anyone can request a new emblem of belief to be added to this list. All you have to do is establish that there is, indeed, a need for the icon, that the deceased sincerely held the belief, and "submit a three-inch diameter, digitized, black and white representation of the requested emblem that is free of copyright or trademark" to the Memorial Products Service, found here:
Memorial Products Service (41B)
Department of Veterans Affairs
5109 Russell Road
Quantico, VA 22134-3903
In the meantime, feel free to choose from the following.