I've tried Wikipedia, searches for "heraldry", "heraldry glossary", "heraldry terms", "heraldry vocabulary", and that sort of thing, (I found this site particularly useful). But my French is pretty limited, so I've come here to beg an answer.
The character is a self-styled Queen with an invented symbol of a silver heater-shaped shield with a golden crown in the position of the chief band, and a crossed nail and rivet below that which form an X shape. Although the setting's not Earth, she's the sort of character who would know the proper way to describe it. Argent a corona or above crossed clou et rivet is the best I can do. Is that close to what I want?
