Sin Metal

Incredibly rare and unique among things mined from the ground, Sin Metal provides an opportunity to dispel and reflect magical abilities, a property that warranted all records of the metal to be purged by the dragonborn following their conquest of Andara.

Properties
Sin Metal is a very dark, matte grey metal of incredible density and weight. The metal is incredibly hard and has an uncanny ability to disperse energy. These properties make it ideal for manufacturing weapons and armor. Due to its rarity and incredibly high melting point, however, arms and armor made of sin metal are rarely seen. Most interesting, however, is the metal's natural ability to dispel (and sometimes even reflect) magical effects cast upon it.

History
Discovered deep within the molten lakes of the Caldera, Sin Metal was first worked by dwarves who were desperately seeking a new weapon to stave off encroaching dragonborn legions. While the dwarves were successfully able to harness the heat produced by molten magma to melt the metal down into a usable form, they were unable to produce large quantities by the time dragonborn occupation forces arrived. Terrified of what might happen if Sin Metal's properties were spread, the dragonborn went to to great lengths to destroy the metal's existence from memory by executing craftsmen, destroying forges, and burning books.