Nathan Duck covers how to create procedural glowing rock under Eevee or Cycles.
If you like shading tutorials and the like in Blender and don’t follow Nathan Duck, maybe you should fix that. Nathan covers how to create a lot of materials and effects in Blender using Eeve, real-time materials, and some that will also work under Cycles. His latest tutorial shows how to create an excellent looking glowing rock material.
The material is procedural, which means that you can build the whole thing without any bitmapped images; everything is sourced right from blender using Voronoi textures and other procedural noises. Nathan’s last tutorial showed how to create a classic-looking 80s style sunset using realtime techniques in Blender With Eevee. Check that one out here.