Mined from mountain ranges in western Khorvaire, this lustrous purple metal is incredibly dense. It is typically worn as jewelry in modern Khorvaire, and is considered a precious metal akin to silver, gold, or platinum. A peculiar property of the material is that certain aberrant creatures seem to have a distinct aversion to the metal. In the days of the Dhakaani Empire, the dhakaani used weapons plated in Byeshk to combat the Daelkyr. Druidic Traditions of the Eldeen Reaches, most often the Wardens of the Wood or the Gatekeepers, still trade with the people of the Byeshk Mountains for byeshk ore to make use of this susceptibility against their ancient enemies.
Byeshk is far too heavy to forge weapons entirely from it, so the Dhakaani used a process of electroplating to apply a thin layer of byeshk to steel or adamantine weapons. Even still, weapons that normally have the light or finesse property lose those properties when plated in byeshk, and weapons that lack those properties gain the heavy property. Additionally, all weapons or armour plated with byeshk weigh twice their normal weight.
Weapons or ammunition coated with byeshk are not inherently magical, but they are unusually effective when used to fight aberrations. Whenever you hit an aberration with a byeshk weapon or piece of ammunition, the weapon ignores the aberrations resistances, and the aberration can’t regain hit points until the start of your next turn.