Immediately when I saw this lovely snake I thought 'chain extender' because of the way he gently curves.
Likely to have originally been a hair ornament. 
He is crafted in silver and set all over with rose cut diamonds in open back settings so although the diamonds are small they really do twinkle.
The crown of his head is set with a .2 carat brown old cut diamond, his eyes with two tiny cabochon rubies in gold.
The reverse is backed with 18 carat gold.
 
He is shown in the photos here clipped onto the albert chain that is on my newsletter today.
 
weighs - 8g
measures - 62mm x 14mm
English circa 1890 - 1900
 
Excellent condition