This artifact is a piece of driftwood that was pried from the hands of one of the victims of the Titanic. It is imbued with the freezing chill of that night. Blowing on the wood creates a wisp of fog, and the person the fog touches will die of hypothermia. But, if the victim somehow manages to retrieve the piece of driftwood, and holds it very tightly, the process is stopped.
It was one of the artifacts Artie traded to the Soviets when he was working for the NSA.
Artie hadn't seen it since, until the NSA director was found dead in his own office. He died of hypothermia, even though it was 70 degrees (Fahrenheit) in his office.