Each item is one of a kind, with unique patina colors, and textures. 
Patina is on both sides of the blank.
Metal - raw brass
Size - 35x15 mm (~ 1.4x0.6")  
I made the photo on my workbench on my mobile phone. So, you can see the natural colors of the patina!
The colors of the patina are natural, and in all processes, no harsh chemicals are used.  
The brass/copper blanks are covered by a thin lacquer layer to save the patina's natural color. 
You can add additional layers of lacquer to protect the finish further.