In my experience some seeds (those with visible seams) are indeed very easy to crack open. However, the majority of seeds do not have visible seams and, consequently, are very difficult to crack open safely. I use wire cutters, and I think I'm probably 1 for 4 or 5 on safely cracking open a seed which isn't already splitting with a visible seam, which is why I don't bother anymore.
It does seem like germination can take some time. I've only had one seed from my first batch (4 months ago) germinate so far. It may be best to just try to nick the shell or attempt to crack it open after allowing the seed to absorb some moisture and soften.