Jet finger rings after finds from South Shields/Arbeia (https://en.wikipedia.org/wiki/Arbeia), ca. 3/4th century AD. Interestingly, a lot of the jet jewelry still show tool traces and are somewhat unevenly, sometimes even crudely made.
Allason-Jones, Lindsay; Miket, Roger. Catalogue of Small Finds from South Shields Roman Fort. Society of Antiquaries of London, 1984. pp. 302