Han Sen could not wait to sleep on a bed of those purple crystal cores. Doing so would be better than rolling on a bed of cash.
Ji Yanran and Han Sen were not professional scientists, so the correct terminology escaped them. What they did know was that the purple crystal cores were anti-material weapons. They were explosive devices that released obliterating energy upon detonation.
The Alliance had similar weaponry, but nothing that came close to the sheer devastation the purple crystal cores could unleash. If they were ever to be used, though, they'd need a detonator.
It took only one core to blow up an entire battleship.
Scanners could not detect their presence, and no known weapon could work as a deterrent. They were always primed for use, so they couldn't be disarmed or disassembled, either.