Gold-tone necklace with compass pendant, lost near Acropolis

I lost my gold-tone necklace yesterday around 3pm near the Acropolis Museum on Dionysiou Areopagitou Street. It's an 18-inch gold-tone chain with a small circular compass pendant about 1 cm across. The pendant has a tiny sapphire at the top and the back is engraved with the letter 'E'. The chain shows a few micro-scratches and is a bit worn, but otherwise intact. It means a lot to me—it's a family keepsake from my grandmother, and I really need to get it back.