The artifact you describe is a personal or pocket seal from the Stuart era, dating back to the 17th century AD. It was discovered with a metal detector in Denmead, Hampshire, in 2006.
These pocket seals were designed to be hung on a short chain or ribbon and carried in a small pocket on the belt of men's pants. The front side of the seal could be pressed into wax to create a seal on documents or correspondence.
The front side of this particular seal features a coat of arms design, which includes horizontal stripes. On the upper portion of these stripes are three running roosters, while the middle stripe contains a small pentagon in its center. The fluted part of the seal bears the initials "EBH," which likely represent the owner's name. However, as of now, the specific identity of the owner of this 17th-century seal has not been determined.
These seals were used to authenticate and secure important documents and correspondence during the Stuart era, and they often featured the personal heraldry or initials of their owners.