Spoilers, obviously:
I just did, after ~21 hours of attempts. (immediately restarted game if the sector map did not display a green->green->red route). Got very lucky and hit engy->zoltan->rock homeworlds in quick succession on the winning attempt.
I can confirm that you get it by:
1. Getting the stasis pod in an engy sector (homeworld or plain) (fairly rare event)
2. Getting it opened in a zoltan sector (homeworld or plain) ('research testing' event, pod gives blue option, fairly common)
3. Getting to the rock homeworlds, and finding the crystal entrance encounter (not sure, could be fairly rare)
This is the layout:
http://cloud.steampowered.com/ugc/59697 ... 11F82428D/
The crystal weapons fire ridiculously slowly (a bit too slowly if you ask me, glaive beam feels faster), but they have a piercing effect.