The Writer glimpsed it in his journeys through the various hells, but he paid no heed to it. His tale was about the afterlife and the punishments therein, not the arms and armor of the Darkness.
The grave robber grinned as he left the royal barrow, his pockets full of stolen gold, and dressed in a helmet and chainmail shirt stolen from the now naked, decomposing body of the king. The explosion that followed ten seconds after he stepped into the sunlight wiped the smile from his face and blew his body into pieces. Had he studied metallurgy, he would have known that the armour was made of pure Orthacarium and he would have left it alone, and escaped the barrow with his life.
The Chinese, when attacking a castle or fort, flew kites over the city wall and used the length of string it took to get it there as a measurement to know how far they had to dig a tunnel to get under the wall.