sorry for the delay in getting back to you on this one - I have only just discovered your cameo medallion bracelet and its unfortunate that the photos you kindly attached are not very clear -would love to know more about the composition/materials of your cameo bracelet - as this style of cameo bracelet with seven round cameo stations was worn by the doomed Marie Antoinette and it is believed she bought the bracelet of seven cameos of Roman emperors surrounded by rubies from Jean-Baptiste Mellerio, the designer, in the 1780s.
Testing the metal on Rosa's cameo bracelet can easily be done. Gold testing kits are available so you can test this yourself but make sure you are careful where you test it as the acid will destroy shell although you mention the cameo stations are hardstone.
This is the cameo bracelet believed to belong to Marie Antoinette - A jewelry expert attested to its 18th-century origins and it does match Marie Antoinette's style of "luxe pauvre".
