18th Century Decade Rings.
Victoria & Albert Museum Collection.
A decade ring has ten bumps around the outside of the shank for use as a prayer counter. The bumps correspond to the ten Aves of the rosary and the bezel, usually having a religious decoration, acts as the Paternoster. In use since the 15th century, they were particularly popular in the 17th and 18th centuries as they were easily concealed during times of religious persecution. Also referred to as rosary rings.