He remembered an old science fiction story, set in the Middle Ages of a world in a far-away galaxy. The hero’s weapon is a sword, its blade honed from a single crystal. This was different. The jade colour of the blade, its transparency, made the material uncertain, implausible even. Yet it was there, the celtic hilt, the cross. The elaborate work of the pommel hinted at a late period, perhaps at the Renaissance. But he knew it was much older. He knew when it had been forged, and the name of the sword smith.
But he could not remember where the furnace was.