If it is hard to tell the difference and it is anodized, I'd say it is probably Ti. Blue, straw, purple, yellow, all typical Ti anodizing colors but they will appear more earthy than a blue or other color anodized piece of aluminum.
Other than density (hard to measure something THAT small without some serious lab quality instrumentation) or the above scratch test (and that might even be slightly destructive depending on how you look at it), there is really not much else that can be done. You say it feels "not as rigid", but Ti is a fairly flexible metal. The big difference would be if it sprung back to the exact same shape. Ti is really hard to bend without heat. Also Ti is not really very hard. It is tough more than hard in most all cases.
If you could sacrifice a tiny piece this would be easy. Touch it to a grind wheel. Brilliant white sparks if it's Ti. Dunk it in lye or Greased Lightning degreaser. If it comes out in one piece, it's Ti, as aluminum will dissolve. Heat it up with a propane torch to red hot. If it's Ti, it'll still be there if Al, it'll be a puddle as soon as the flame hits it. Walk in with the announcement that you are going to do any of the above and see if the vendor has a cow... heheh.