Are these natural or manufactured stones? Can you drill them for use as buttons? (cost $) Do you have natural amber cabs and rounds available? What are the thicknesses since I intend to use these pieces as buttons?

Tiger eye is a natural stone. You could drill them and use them as buttons. The thickness varies by size but they are usually around 6mm in the center to about 3mm to the edges. Please search # 81.030 for our amber cabs.