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 - 40x30 mm (~ 1.5"x1.2")  
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, all processes no harsh chemicals are used.  
The brass/copper blanks are covered by a thin layer of lacquer in order to save the natural color of the patina. 
You can add additional layers of lacquer to further protect the finish.