Rare Georgian Harlequin Ring circa 1820-30.
Eternity like in style with full band of stones in silver cut down settings but with a larger central stone, flanked by three stones each side -
 
with gemstones including, amethyst, sapphire, ruby, chrysoberyl, garnet, pearl, yellow sapphire, hessonite, emerald, jet, chrysoberyl cats eye, pyrite, moonstone, carnelian.
 
It may be a planetary ring with the stones representing  the qualities of the different planets, reflecting the keen interest in astrology and planetary influences at the time. Certain gems were perceived to have positive astrological effects.
 
Saturn - sapphire
Venus -agate 
Mars -red coral  
Jupiter- amethyst/yellow sapphire  
Mercury- garnet/emerald 
Sun center ruby
Venus - diamond
North Node Ketu/chrysoberyl
Pearl/moon
Rahu/hessonite
 
I was wondering if the central stone was the person's birth stone, with the stones flanking on either side either related planets (rising etcc) or family stones.
 
Size 7
 
central stone about 6mm diameter
 
a couple of stones have chips and wear but more towards the back of the ring and are miniscule and only noticeable under a loupe.