what scientifically accurate means in regards to materials especially metal
Aluminium is an interesting metal: That whitish surface effect seen in real-world aluminium samples consists of a layer of Aluminium III Oxide (alumina) 4 to 6 nanometers thick, which forms almost instantly (in picoseconds, according to Wikipedia) when a newly machined aluminium surface is exposed to air.
This form of aluminium oxide is an
opaque white ceramic material with low specularity. To render it, one might try adding a low opacity label of a material with white diffuse and dark grey specular values over the aluminium.
I had expected the "anodized" parameters of the metal to yield some useful result, but at an anodization thickness of 4 to 5 nanometers, there seems to be no visible effect, and beyond that a yellowish tint appears. The white powdery effect doesn't show up.
The other such problematic metal to render is titanium: Again, real-world titanium instantly forms an abrasion-resistant, low specularity oxide layer of 1 to 2 nanometers, which 3D rendering engines don't seem to offer a way to simulate.
If someone does figure out a way to render that oxide coating realistically, it would be invaluable for some of my work, so please share!.
(n.b. I'm using the IUPAC spelling of Aluminium by choice, rather than the Americanized "Aluminum")