Signet Matrix: Seal Matrix featuring Joseph Priestley

A seal matrix of octagonal shape, made of purple glass with a design of the head of Joseph Priestley, facing left. Priestley died in 1804 and the matrix was probably after his death in that year.

Seal matrices also known as signet matrices were used to impress their owner’s mark into wax on documents during the eighteenth and nineteenth centuries. Many were made of moulded translucent glass. Little is known of their manufacture. They seem to have been produced for personal rather than commercial use. Birmingham Museums & Art Gallery acquired a collection of twenty-seven seal matrices in 1934. This is one of the items.