Best guess, 13Mhz. Give that a shot and see what happens. Unfortunate the act of measuring the crystal changes the load on it and the frequency it puts out, but it was still able to talk to my 7e while running at that estimated 13mhz (could be 14) so that is at least close.
Add in that I'm doing this on an old analog oscilloscope and I give it a +/- of 10%.
EDIT: I hot glue mine too.