i wouldnt like to say any pill is OK, whatever that means...
a crumbly pill may mean that it has been poorly pressed by amateurs, and probably doesnt contain MDMA, only speed and other crap...
BUT a crumbly pill could also just be old and have become crumbly due to being stored in overly moist conditions...
a hard press is also no guarentee of a "good" pill. we have seen a lot of localy made speed bombs lately with a very professional looking hard press.
the only way to kow for sure if your pill contains an "xtc" substance is to test it with a kit like the EZ Tester or Dancesafe kit... anyone who thinks they can tell by just looking at a pill is fooling themselves...