Urasylium is a mineral that is extremely rare in both Jura and Nihari, so rare that it was barely known to exist only recently even in Nihari.
It is mentioned in the report about it that the largest piece of that mineral found on the planet Jura was a tiny bar as big as a finger.
After the features of the metal bar were identified back then, that little piece was delivered to the king of the Kingdom of Oaklea who had knowledge about the Minor Heavenly Laws related to ground and minerals.
But even that old king had to give up in the end, leaving the metal bar aside as one of the symbols of his kingdom.