Unusual neoclassical hardstone urn cameo pin c.1800.
The extra long pin was a feature of some Georgian brooches  often described as a comet motif.
Hardstone urn cameos are much more commonly found in mourning rings of the 1770s but occasionally in other forms.
High carat gold. 
Cameo 1.5 cms by 1.2 cms. Pin 4.5 cms.