Fabulous Georgian Optical Illusion Ring.
This black enamelled mourning ring is designed with two rings of gold on the band that are raised and engraved with angled lines that mirror one another, sothat when you rotate it on the finger the gold circles seem to wave in and out. (if you know what I mean!)
The inside of the ring bears the inscription - 
'Ann Miller Ob 22 May 1819 Aet 87'
weight - 5.3g
size - 6.75
width - 8mm
18 carat gold
In good antique condition