I came upon this finish...

Click image for larger version. 

Name:	Finish.jpg 
Views:	507 
Size:	316.8 KB 
ID:	43918

Does someone know the technique, how to achieve this, or is it just a matter of wood? I tried to find some information...
What I came upon is that you "sand" out with a metal brush the softer woodparts and the hard parts stay, so you get a kind of relief...But it must be a whole piece of wood with interesting grain that gives the opportunity I suppose...