It's very coming in the Arabic poetry to liken pretty girls to harvest moon .. In the past it used to mean that the girl is very white skinned and has a round face, her face is bright as moon .. But know it's common say so about any pretty girl not necessarily what i mentioned.

It's also very common in the Arabian Gulf to liken the beloved girl to pearls and diamonds, to show how precious they are, and how will the man will keep her protected and saved in a safe place.