Antique pearl earring

Hello I’ve just rediscovered this lovely pearl earring , most of the pearls have had the gold taken , but this one still has the post which is marked 9 c , looks really old and I normally only see antique items marked like that. It’s quite big and looks like a good quality pearl, no idea what kind it is or if it’s worth much. But I think pearls are back in fashion and I’ve even seen grown men wearing pearl necklaces on TV, how times have changed LOL