For this project, I downloaded a bunch of reference images first and modeled the basic head shape of the Mjolnir with correct proportions. A fairly simple thing. But I wanted the handle to have procedural material that I can change as I wish. It would've been easy to probably use a screw modifier with boolean, but I buy my own complications so procedural it is. Not gonna lie, I am pretty proud of the result.

After the handle, I moved to the runes and inscriptions on the head. In a sneaky way, I searched for black and white images of the runes and used them to drive the normal. For other simple indentations, I used booleans. With a metallic material, the head was complete.

Then I moved to the strap. That is just a curve extruded with a leather-like material. I then set up a basic scene. The ground is a plane with Displace modifier and stones scattered on it through a particle system. I developed a reluctance towards PBR textures lately. I want everything to be procedural with full control. but I was not happy with the stone material I made. So I finally just used a PBR texture for them. In the compositing tab, I made a sky gradient. Depth of field will make anything look realistic!