Celebrim
Legend
I like the stylized quill, but if your players don't, perhaps a stylized transit (the surveying tool), which measures the natural world and helps build cities?
Good call. I like that.
Although, the transit is a 19th century invention, the more ancient devices are appropriate and make interesting symbols when stylized.
See Circumferentor, and Graphometerfor examples.
But taking your idea and running with it, I think even more perfect is a Plumb Bob. It fits think it fits perfectly with the idea of a god of knowledge, cities, and order that he would be symbolized with by a tool used to make things straight. The Compass is another good choice.