AVR-Chat

The idea that all crystals are the same should be taken out back,
shot, burned, and the ashes should be scattered.

It is common practice to ground the shield can of crystals, but there
are certainly some that aren't designed for this, and even some that
aren't capable of being soldered. Some have a third lead so that the
can doesn't have to be directly soldered to.

It's up to the designer to select the proper crystal for the
application, which includes reading and understanding the specs.

Then we can talk about drive levels, and loading capacitance.