Vin's mother's earring

Vin's mother's earring, a subtle Hemalurgic spike disguised as simple jewelry, plays a pivotal role in the Mistborn series by serving as the vessel for Ruin's insidious influence over Vin. Passed down from her mother, it lurks unnoticed until its true nature is revealed in the climactic events of The Hero of Ages, where it nearly dooms the world by compelling Vin to unleash Ruin's destructive power. This unassuming artifact underscores the series' themes of hidden corruption and the perils of unchecked power, evolving from a forgotten trinket to a linchpin of cosmic peril.