Micro Mosaic Brooch depicting a bird on a branch set in silver.

It gives me great pleasure to show you another of my "conquests" in my passion for antique Micro Mosaic jewels. A beautiful antique brooch depicting a bird on a branch with tiny blue flowers. In my estimation, and see these tiny tesserae, this brooch was made around 1860. Maybe something earlier. The diameter of the brooch is 2.8 cm (1.1 "). I think there is a hallmark on the c-clasp but I can, even using a magnifying glass, not decipher. I bought it as silver but I'm not even sure if the mounting is silver, gold or gold plated. Does anyone have a more precise idea of the year in which the pins may be made of ?
I would like to hear your vision?