Mother-of-Pearl Table Seal, Victorian

This circa 1850 mother-of-pearl table seal is very interesting. It has an intaglio in the top and the bottom. The bottom appears to be a scribe which looks like "MMD." I can't figure the top out. It looks like something written in Greek letters. Any Greek scholars out there? Anyway, the piece is a solid piece of Mother-of-pearl, and in excellent condition. It is 1 and 1/2 inches tall, and the oval across the top is 2/4 of an inch, East to West.