Antique Italian Grand Tour Rome Micro Mosaic Plaque set in Heavy 14k Gold Clasp, Bracelet?

The River Arno landscape as subject, this large and fine mid-1800s Italian micro mosaic plaque mounted in its 14k gold mount (a complete clasp) comes from a rather large stash I bought as a Paris goldsmith's estate was auctioned off. Everything from jeweler's tools to unmounted stones, cameo, micro mosaics. Among those were sections of what must have once been a bracelet or perhaps even a necklace. I have 4, and they are listed separately. You see some of them in the final photos I've sold off a lot of others - those are the remainders I'd kept. You are buying just one - this oval black slate basin simple landscape including the River Arno near the Roman ruins.  Ready to make up into bespoke jewelry (is it Elizabethe Locke who has done some masterpieces with these at enormous prices?). Or just collect them as I have, as the small wondrous works of glass art they truly are. Each tiny colored glass tesserae worked into the onyx or black marble basin, filed smooth.  Full measurements note