Mark on earrings-Greek?

[awtonomows]

Can someone help identify what looks like Greek letters on this turquoise and silver pair of earrings and/or what they mean? The upside down mark is 950 which I believe is silver content? Thanks much!

[mkad]

The Greek signatures are a bit like the Mexican ones. City ID, in this case Omega Delta is Athens, and the silversmith's ID number, 19, which is unfortunately harder to find than even the Mexican numbers.

[awtonomows]

Thank you! That helps a bunch!