I created a tileable rock texture from a piece of a photograph taken by my father (with his permission). Again this image is fully tileable, suitable for 3D models. Also, it is extremely high resolution because I tiled the original image and made the resulting image tilable as well.
Tile tile tile.
Example of texture in use at: [link]
This image is stock and may be used in deviantART deviations without permission; however, you must post a comment here telling me where you used the image. Prints incorporating this work are probably okay, just ask. Use outside of deviantART may be acceptable, but ask for permission first.
Download for fullsize (7008x2336)