Hey guys, just letting you know, I went further and will continue in the evening. I will soon share my file with the tweaks I went for. I hope you have a lovely weekend! 
PD: I’m so sorry guys, but I ran out of time this evening. I’m preparing 4-5 different kinda stones, and will tile 'em up, but it takes time. If you proceeded any further, feel free to post it below. Cheers!
Hi All,
I think I am nearly finished, I will share this now, and feel free to tweak it from here. I used 3 types of rocks only, the RGB channels were great to separate them. Roughness would need to be added, also the textures and bump could be better, but I speed-ran it really 
The point is not the textures I guess, but the basic setup, the actual textures can be changed or replaced. The stones with the double top can also be checked, the way I solved it.
Also, the masking is a bit confusing, there could have been an easier way, but I came up with it on the go, so there may be some unnecessary duplications in that regard, please keep it in mind 
Also, the .blend is set to factory settings almost, so you may want to copy the object out to your own setup
STONE WALL 3ways.blend (1.3 MB)
that is one sexy tree!
Arousing, is it? 
First of all I want to thank you, because your texture is absolutely impressive 
. But can I ask a few more things?
The bump should be rounded (not flat).
Secondly, I would like to be able to apply this texture on very large walls. I tried on a small wall, but my PC almost caught fire Is it possible to use it on a large surface according to you?
Hi there,
Thank you for the kind reply. My PC is also an older rig, I really need a new one 
If you don’t need the different kinda stones, you can leave that, the smooth minimum, colour burn and colour dodge controls the size of the bricks and acts as a mask as well.
The bump looks flat because I cut it from ortographic view. With a more refined voronoi, it can be really good.
The larger the texture the harder it is to compute but with only one type of stone, it shall be much easier.
If you like, I can create you a refined version with only the gray bricks with the double top
I’ll try tomorrow on a more powerful server (my pc has only an old NVidia GTX970M).
Yes, if you can create a ligth version, i can look with my PC.
Thanks a lot for your work 
The first video is not very easy to follow ! Speaker to quick, does’nt give the keys … and the model is no where to download !!
I try i try but it’s hard !!!
If you like, I can try and create a nicer version, with only the doubletop kinda stones, and share here 
I’m lost in the middle of the first video on the bricks …
Yes, if you have a more simple solution, i’d like to try it instead of this huge example.
Alrightie What I can do is simpifying this one, and may also create one without the vertex math part at the beginning. I will start this evening, and will hurry, and share, but may take a few days to come up with something else from scratch.
Although, one of the corner stones of procedural texturing is the vector based coordinate systems upon which the texture is placed upon, so I urge you to look into those as well, maybe with a simpler tutorial.
I cam advise you on checking Sam Bowman’s, and Default Cube’s youtube channels
Hi there,
Please kindly see this version. You could play a lot more with the colours, but I got fed up with setting one I like haha 
If you load any image to the image editor, and split your window, you can hover over a color ramp, to the actual ramp part. When you see the eyedropper, hit “E”, then go over to your picture, and click-drag, and (I guess up to 30) colours will appear on your color ramp.
So for cases like this, you can actually find a real stone wall photo, or anything else you replicate procedurally, and grab the colours from there 
STONE WALL new.blend (1.7 MB)
This an actual wall http://www.maquetland.com/upload/phototeque/images/10507/montpellier_tour_pins%20(4).JPG
I am impressed with what can be done with the shader !
But, alas there is a but … the “bump” of the type of wall that I try to reproduce is “rounded” and not flat (as you can see a little on the link).
Your model is really beautiful (it took me a while to render it on my PC!!!). The color doesn’t bother me too much, I did understand that it would be possible to change the colors.
Thank you I can try to put it on an actual tower. At first I thought you want to reach just the rounded brick, with some variations. Not adding it on a tower can be possible, sure, but the variety of the grander structure would need to be added.
You can actually solve displacement with not two, but only one RGB Curves node, you simple add the two steps together, just came to my mind later Oooor, maybe not, if you want to control the top and bottom shapes differently. But to some extent, it can be a simplification:
Anyways, with great, tileable PBR textures, you may actually reach your goal faster, even though it may not be as much tweakable.
Regarding the bump, I added displacement only for those, but the rest is solved with bump, to save resources. In theory, you can combine the stone texture with the displacement, so it will really be popping our physically for the stone surface as well. But it would take more tweaking and system resources though
Little question about the size of the texture. On my wall, the texture is stretch along the wall. How can i “resize” the texture (and rotate it too !!).
Yes i’m newbie on texture (and blender too 
)
Hi, sorry I might not have seen a notification about your question.
Well, if you add a mapping node right after the texture coordinate, you can fine-tune the rotation and scale along the three axes
cmd+a “apply scale” is to keep in mind too
If it’s round as in cylindrical, you can use this trick to manipulate the coordinates, maybe:
.JPG){kind=link}