Gavin's signet ring

Captain Gavin MacLeod once owned a signet ring.

After the death of his parents, Gavin became a trading ship captain and set sail to America in 1723, only to die along with his entire crew in Massachusetts.

Many years later, a couple of "Cousteau wannabes" found the wreckage and collected Gavin's signet ring. The ring ended up becoming part of the Treasures from the Deep exhibit at the Maritime Museum at Andover.

In a bid to learn more about Crowley's human life, Bobby Singer orders Rufus Turner to obtain this ring. Unfortunately, upon snagging the ring, Rufus gets chased by the police. Rufus calls Bobby to inform him of the situation, and through miscommunication, Rufus swallows the ring against Bobby's wishes.

Rufus ends up in prison, forcing Bobby to ask in a favor from Sheriff Jody Mills. The plan is a success and Rufus arrives at Bobby's house, the ring no longer in his stomach, though Bobby insists on boiling in hot water.

Bobby then uses the ring in a summoning ritual, and speaks with Gavin's ghost. Out of pure distaste for his father, Gavin tells Bobby everything he wants to know.

Afterwards, it is unknown what happened to the ring. A few years later, Abaddon drags Gavin from the past to the present timeline. Oddly, Gavin is not shown wearing his ring, despite being in the process of packing his stuff to set sail.

Appearances
Season 6
 * Weekend at Bobby's

Trivia

 * If Bobby had kept the ring inside his house after using it, it is possible that the ring was destroyed along with the fire that took down Bobby's house a couple of months later.
 * This would also mean that Gavin's signet ring exists only in the past, where he may have left it.