Very attractive high carat fob from the early 19th century, modelled as two serpents with rather dolphin like faces, coiled together in a spiral, their tails forming two loops at the top to hold a chain, or split ring.
I have some other snake fobs at the moment and if you look at the final two images you can see how fab they all look on an ouroboros split ring together!
 
The base is a rectangular uncut carnelian
 
measures - 22mm tall
base 17mm x 12mm
weighs - 6.9g
english circa 1820 -30
excellent condition