On Fri, 18 Mar 2016 14:05:57 -0500, Jon Elson wrote:

If these things are on TOP of the coating, then it should be easier to
make a conductivity measurement. (But, yes, I see you say they are
brittle.)

Indeed they are - very! Anyone who can come up with a method for
establishing if they're conductive and if so, to what extent deserves a
Nobel Prize, I reckon.