Hi Carol,
Its a bit difficult to tell from the picture but looks like the Chester hallmark for 1909. This is a a typical English 'sweetheart' brooch of the period. The maker's mark is unknown to me (and I can't find it).
David
Maker is Harry and Charles Banks, trading as H & C Banks, manufacturing jewellers of 41, Northampton Street, Birmingham. They entered their first mark at the Chester Assay Office on the 12th January 1907.