Sterling silver necklace, Whitby jet

Beautiful sterling silver necklace 22 inch chain.  With small Whitby Jet pendant  filigree, from our British collection?
 
Whitby Jet workshops were established in York in Roman times and many ornaments have been found there. As it was a cosmopolitan city we must be careful not to assume that all jet in York came from Whitby. Spain also had supplies of jet and the Romans were adept at bringing the luxuries of their empire to markets. In Anglo-Saxon times jet continued in popularity, and there are many objects of jet from the site of Streanaeshalch.