Jeff, the jargon of heraldry (called "blazon") is indeed from old French and even today's French speakers would have a hard time understanding it. I'm an amateur at it myself, but there are people who still study it extensively.

Just FYI William Balbirnie's work on the Balbirnie family (details posted separately on this forum under the "William Balbirnie" thread) describes two Balbirnie families in Forfarshire in Scotland, one "Balbirnies of that ilk" (meaning "Balbirnies from the area called Balbirnie") and one "Balbirnies of Inverighty", and two similar coats of arms for the two families. His line - the Balbirnies of Inverighty, the line he says survived - have arms described in blazon as "Vert, a fesse chequy argent and
azure between three curiasses or Hybergeons of the second and in a chief of the same three
buckles of the third." In picture form that looks like the file I attached here. I don't know how close that matches the description you have.

Dave Vance