Copper is a very 'active' or better yet 'reactive' material. From the day it is made, your marker will begin to react and change as it is used and exposed to the world we live in.
Colors will fade, low areas will develop a rich caramel color, and high spots and edges will become shiny and more golden in color.
Aluminum does not visibly patina, but it is a soft metal that will age gracefully with use and develop its own rich character.
Over time, these markers will age and take on their own unique personality!