Here's an interesting background I made yesterday using a photo of a red jasper. Left version is the non shaded version, right is the shaded and enhance version. I used the clone tool to create extra texture area, which means this doesn't look just like the pendant, but it still has some kind of background appeal like a volcano spitting.
This is inspired off of what I see in the actual stone (left). I love this pendant because I see a little illustration in it. In the corner you have the silhouette of a rock cliff or the top of a volcano, the bright red streaks being the lava which erupts and spews through the darkened sky of clouds which reflect the glow of fire.
The setting only makes it even more beautiful, like an oval sun.
I made the background images as an experiment, wishing I could have a painting that looks like this stone.
Playing with it in PSE helped me accomplish something similar to an actual textured painting, but I would still love to have a real painting of it for the aesthetic of acrylic paint texture. I like the depth of actual paintings, and the fact they can be fun to touch.