i lied
weaponry. obviously no society is perfect, and weapons will be needed in one form or another in order to keep peace, so heres my ideas thus far
firearms: these could be rifles and pistols that store water in there stalks and keep a grain of the rock separate. pull back the hammer, and a drop of water is added to the grain, and it builds pressure. pull the trigger and the steam is released, the grain is attached to the metal so it dosnt fly off with it, and the steam pushes a steel ball out at high speeds
small explosives:
a grenade could be a sphere filled with water and a grain of steamrock inside a sealed cylinder attached to a knob on the top which, when turned, opens the cylinder exposing the grain to the water. in a few seconds, BOOM. hot steam and shrapnel result.
rocketry: a grain is exposed to a water tank, and the only place for the steam to go is through a very small hole in the back. the small hole would allow the rocket to generate enough pressure and sustain for long enough to launch a small rocket a good distance. but that would probably be fairly inaccurate so these would be launched as a 30 rocket battery or something like that.
also i was thinking about typical personal belongings. i was thinking that everyone owns there own piece of the rock, and it is used to power things. example, you use your rock to power your car to get to work, get out and pull your rock out, go inside and put it into your work machine (whatever it may be). everyone owns ONE rock that can be used for anything.
maybe make it so the rock can be put into a little nest on the machine and the steam creating energies are directed at the water source? in this case a marble size peice could be used for practically anything
aand my storyline idea
if this rock doesn't intake anything before outputting, that literally creates a kind of glitch in the universe. i was thinking, as a storyline element, that these rocks need to be in the sun for a little while before being used, but at first ppl didn't know this. the rock had been flying around in space for god knows how long before coming to earth, and that energy lasted a long time. ppl thought the energy source was infinite/self sustaining and built things around it in a way that the rocks couldn't be removed without destroying the machine that uses it, causing a huge amount of problems just before the aliens invaded, making much infrastructure collapse just before the invasion. also (if it were a game) we could use this to make puzzle elements centered around retrofitting things or refilling them with energy before use
