One thing that might help you is understanding how that material is achieved in real life.
The "anodized" part is not very important, as it is essentially changing the color of the surface (the resulting microscopic structure from anodizing is so small that we can just ignore it and assume the metal to be that color, just like gold or copper)
The important part is the sandblasted texture. Accheived by shooting a stream of very fine "sand" into the surface, the sand is made from a material that is stronger than the metal itself, so every time it hits it, it creates a tiny crater, removing a tiny amount of material.
Here is a couple of images I took with a microscope.