Here's a cool idea:

Like the band of stability for atomic nuclei, which become radioactive beyond a certain size and decay, the same might be true for crystalline molecular structures. Up to a certain size they are stable and behave classically, predictably. Beyond that size they exhibit really wierd effects, like exerting forces on space & time in a reactionless system; catalyzing the creation of and emitting large quantities of exotic particles like antimatter; or negative matter when squeezed; trapping light or entangling photons in a stable manner; opening see-through wormholes into the past.

Imagine for instance, that an astronaut is experimenting with a fist-sized "perfect" crystal of a relatively common substance, and he loses his grip. It goes spinning away inside the space station. He pushes off the floor and reaches out to grab it. He just at that instant he grabs it he sees his reflection in its faceted surface - the reflection of himself coming towards it and grabbing it. The crystal shows a delayed reflection, one of him a few seconds earlier !!! Suppose this effect increased with the size of the crystal, and we are able to see into the past by days, years, millennia, eons!!! Finally a crystal ball that actually conjures real images. LOL

But seriously, what if large perfect crystals could be used to catalyze antimatter production? That alone would be an incredible discovery, and would open a whole new era in human space exploration.