These rare ships are simply nearly-solid asteroids fitted with weapons and used by spacegoing xorn on their rare and mysterious forays into space. Stoneships do not truly have blunt rams built on them, but rather the virtually solid stone ship itself can serve as a blunt ram. Sages generally believe that these spacegoing xorn are searching for a perfect world to colonize. Since Stoneships are the perfect size for smaller dwarven citadels, the asteroids are sometimes boarded by dwarves with the intent of converting them. Since the Stoneship generally appears to simply be a lifeless asteroid, often the dwarves are unaware that it is already inhabited until the xorn start attacking. This of course leads to a vicious, protracted battle that can last for months or years before either the dwarves or the xorn are exterminated.
Stoneships are powered by fire elementals harnessed through unknown magics that other races have yet to discover. In fact, the xorn are incredibly secretive about this power source, to the extent that they will power down and banish all apparatus and traces of its use whenever intruders are detected aboard a Stoneship. This power source is always enclosed in sealed, interior caverns with no access tunnels. Xorn phase into and out of such caverns at will but other races, even those able to take gaseous form, are unable to enter without powerful magic or extensive digging. Because these caverns are completely airtight, it seems to be possible to use this power source even in the phlogiston where the fire elementals would normally explode. On at least one occasion a Stoneship in the flow was boarded by dwarves. The xorn seem to have been worried that the dwarves may discover the source of their power, and, being unable to banish the elementals back to their home plane, created a fissure in the stone, exposing the elementals to the phlogiston, and causing a massive explosion which destroyed all traces of the power source.
The crew sizes given above are estimates based on human-sized crews. It is believed that only 8 xorn are needed to operate a Stoneship, and 2 per heavy weapon, while a typical crew will number approximately 40.
Explorer: It is not known for certain if this is the use to which the xorn put their Stoneships, but to all appearances this is their function. They have certainly not been seen to function in any other roles.
No other configurations of Stoneships are known, unless those captured by dwarves and partially converted into Citadels are counted.