Hey there! Thanks for checking this out, I present to you, a fully procedural customizable semi-realistic rock texture for free :D
It's available on my Gumroad
Although the nodes may seem a little complex at first sight, it's not. It's made by simply layering different Voronoi and noise patterns on top of each other, and you can create your own variations however you like! that's the best part about procedural textures, Hope you have fun!
I downloaded the file, there is only a sphere in without any rock material attached
Thomas. I also downloaded it. Switch to Cycles and render preview on viewport shading. It works perfectly fine. ;)