The Lightwood family ring is a silver ring worn as an heirloom by the members of the Lightwood family. In the center of the ring is the letter "L" surrounded by flames, the Lightwood family symbol, which is etched around the outer surface.
The Lightwood ring was worn in 1878 by Gideon Lightwood. When the members of the London Institute came to try and blackmail Benedict Lightwood, Gideon allied himself with the Institute. When Benedict told him that doing so would be turning his back on his family, Gideon took off the ring and left it on Benedict's desk.