Antique Art Nouveau French Designer Signed Lady Sunset Gold Brooch

This is a really well made high end piece. It is signed but I am unable to make out the entire signature. Very secure trumpet clasp characteristic of pieces of that period coming from France. I am unsure as the to the composition of the metal and if it is not gold I dont want to do damage to the piece. I am listing it now but may change price after I have it XRF tested for metal content. It has the look of a high karat gold and either way it is a beautiful piece. Measurements and weight are in photos