just set up a small quick connect that you can plug the crystals into that's got a small power supply (voltage based on the crystal being tested) and the scope probes connected to it, that's all you need, the hardest part will be if you have surface mount crystals, and dialing in the scope to the right window.
NO, Greengiant
the crystal will have to plug into an oscillator circuit.
You may be thinking of oscillator modules like this.....
one of the easiest circuits would be a colpitts oscillator here's a garanteed working cct I have used often....
That pdf file John has linked to give plenty of ideas of different types of oscillators
including the colpitts
to the Op .... you are most likely going to need a frequency counter unless you have a really decent scope capable of good resolution well above any crystal freq you are testing
freq counters are pretty cheap these days for one that goes to ~ 1GHz
Ohhhh .... if you are going over ~ 4MHz you may need to upgrade the transistors to a higher freq transistor, a BF494 or something similar
cheers
Dave