Simple Art Nouveau onyx signet ring. This ring is in lovely condition and has a big impact. The onyx is a flat oval shape set in a yellow gold full bezel and framed by another gold frame in a simple, shiny finish. The shoulders are a tapered dome simply designed but elegant.
 
I can identify the mark on the outside of the shank. It is ET, which is a "warning mark that indicated that the item, whether gold or silver, was below minimum French fineness standards" which was typically 18k gold. It also refers to the piece being sold at public auction "acting like a pawn shop". So this piece was imported to France and than resold at a French municipality.

This is a great statement ring for your middle finger or awesome pinky ring for your stud muffin.

Gemstone: Flat Oval
Measurements: 15.0 x 11 x 2.3 mm

Width: 18.2 x 13.9 mm / 7 - 2.1 mm wide shank / 4.2 mm high off finger
Metal: 14k yellow gold
Markings: Hallmarked inside and outside shank (difficult to decipher)
Finger Size: 6.75 (shows as 6.5 on mandrel but fits like a 6.75)
Weight: 4.6 grams
Circa: 1910's
Condition Rating: 7 (stone and mounting have had a polish, some wear on bezel, shows previous sizing)

*World Hallmarks Volume I