What a lovely snake ring, the head set with a pear shaped turquoise, the high carat gold finely chased with scales, eyes and teeth. The snake’s head coils around it’s tail - as you can see. He dates from around 1840, and although not hallmarked I have had similar relatives from this period, and actually I have three others at the moment who are also available (see additional pics)
Just under a size 9 
and weighing 5.9g 
English circa 1840