1. Open a new document of the desired size.

2. Reset the swatches (press 'D').

3. Apply the Render Clouds filter (Filter > Render > Render Clouds)

5. To define the stones edges apply the Palette Knife filter (Filter > Artistic > Palette Knife) with the following settings:

- Stroke Size: 50
- Stroke Detail: 2
- Softness: 0

6. Apply the Paint Daubs filter (Filter > Artistic > Paint Daubs) to put the edges into evidence.

Settings:
- Size: 3
- Sharpness: 13
- Brush Type: Dark Rough

7. Apply the Craquelure filter (Filter > Texture > Craquelure) to texturize the stones.

Settings
- Crack Spacing: 22
- Crack Depth: 1
- Crack Brightness: 5

8. Now use the Watercolor filter (Filter > Artistic > Watercolor) to give the "painting" feeling.

Settings:
- Brush Detail: 2
- Shadow Intensity: 3
- Texture: 1

9. Use the Poster Edges filter (Filter > Artistic > Poster Edges) to smooth the image.

Settings:
- Edge Thickness: 10
- Edge Intensity: 0
- Posterization: 5

10. To add color to the texture create a new (Layer > New Adjustment Layer > Hue/Saturation), check the Colorize option and play with the hue/saturation values). Rename this layer as "Stone Diffuse"

11. If you need to use this texture in a 3D Software, you can create a Bump and Specular Map (you can use the same for both the purposes): select the layer used at point 9 and use the Magic Wand Tool (Tolerance=0) to select the black areas (see picture)

12. Create a new layer, bring it above the Hue/Saturation Adjustment Layer, invert the selection (Ctrl + Shift + 'I') and expand it by 2 pixels (Select > Modify > Expand)

14. Fill the selection with white and use the Stroke and Inner Glow styles (click here to see settings)

15. Set the layer blending mode to "Darken", set the Hue/Saturation Adjustment Layer to invisible, Select All (Ctrl + 'A') and Copy Merged (Shift + Ctrl + 'C')

16. Paste the copied image (Ctrl + 'V') and apply the Gaussain Blur (Filter > Blur > Gaussian Blur) with a radius of 3.0

17. Use the Auto Levels Tool (Shift + Ctrl + 'L') and you should obtain a layer similar to the picture on the right. Rename this layer as "Stone Bump"

(optional)
To give a more realistic look, from point 10 select the black edges with the Magic Wand Tool (Tolerance: 0), Add some noise (Filter > Noise > Add Noise) and then smooth it with the Gaussian Blur filter. You can make this on a separate layer (above the Hue Saturation one) to have more control on the color differences.

18. Now in your 3D Software create a material with a diffuse map (point 9) and a Specular And Bump Map (point 17) - use high values for the specular and bump levels.

In the picture you can see a possible results (only 1 light and 1 mesh).

This example was created with Rhino3D.

Click on the image to enlarge