Is there any way to identify different Aluminum alloys?

[Philipintexas]

I'm always finding chunks of mystery metal that are drops without any identification, is there any way (At home) to ID different alloys of aluminum? I can usually tell by machining 6061 or 7075 by the ease with which one cuts vs the other. But, Can I tell without cutting??

 

[Philipintexas]

I may have answered my own question. I'm working on a piece of "mystery" aluminum, I believe it is "Fortal" (7075?) Aluminum I buy on Ebay, but no identification on it.
I machined a sharp edge and used a de-burring tool to clean the edge. The tool made a high pitched scraping sound almost like stone. It failed to produce a continuous chip, kind of small easily broken chips.
I then did the same thing to a piece of known 6061, the same tool made a soft cutting sound and curled off a continuous chip.
I may not know what the alloy is, but I know it's not 6061.

Still would be nice to be able to perform a simple test to know what the alloy is.