Smelling is no sure way to tell if it's MDMA.
While some impurities can have a strong odor, really good MDMA has no smell whatsoever. I've come across a lot of impure MDMA, ranging from purple to brown in colour that still has no noticeable smell...
There is small amounts of MDMA crystal getting around and the fact that the cap is only 1/3 full is a good sign. The only way to confirm if it is an MD** type substance is by reagent testing the contents. There is a good chance that it could be a research chemical so be careful.