English, 13/14th century.
Ring size P UK / 7 US.
The bezel measures 1 x 0.8cm.
Weighs 3 grams.
During the Middle Ages, gemstones were often associated magical and protective properties that they were believed to possess. Gemstones could protect against evil or poisons as well as heightening the individuals’ characteristics and strengths.
For a similar example see the Victoria and Albert Museum, London, Accession number: 639-1871.