I dunno, I read the article and the "guy a thousand miles away" gave pretty damn good reasoning why it'd be short work to identify and categorize "alien alloys".
Or do you have an actual argument as to why these materials couldn't be readily identified and studied by competent physicists using well known technology?
Structure is the basis for 'invisibility cloaks', materials with small-scale structures which confer optical properties not found in the same unstructured bulk materials. [1]
Another example of where structure confers strange properties on elements (not alloys) is light emission from indirect-gap materials like silicon. Make silicon particles small enough and you can get light emission that you can't from bulk silicon. See quantum dots [2] and other similar structures.
That’s the issue, which really comes down to the word “Alloy” in this case. If you believe there’s a chance that the word alloy was used instead of a more accurate and technical term, then your points definitely stand. If they really meant alloy though? I’d tend to side it’s the article. I mean you can imagine some strange and exotic materials maintained by some kind of alien power source, but lose the power and the material should decay in some fashion. For a purely fictional example see things like degenerate matter held in some kind of sci-fi stasis.
If it is Earthish temperature, it going to be made of normal atoms (i.e. elements we have identified on the periodic table) and mass spectrometry and X-ray crystallography would be common tools that physicists would use to identify its molecular structures. And yes, highly advanced nanotechnology uses regular old atoms, as far as Science can see today.
Or do you have an actual argument as to why these materials couldn't be readily identified and studied by competent physicists using well known technology?