I was recently asked to look at a dark blue scale appearing on the exterior of some copper piping and determine possible causes and if any human health risk is likely.  I am asking here primarily for anyone who's possibly seen this blue scale appear in similar installation.  I don't want to take anyone's time going deep as this is a paid consulting task and I do have access to other resources (and this one appears complicated.)  This group has seen and experienced so much collectively though that I couldn't pass it up as a great sounding board.  Then again, most on this list are being rewarded in some manner through the advice, ideas and answers obtained through the group so my shame isn't too unbearable.