Lee Scoresby's mother's ring was a silver, stone encrusted ring, originally owned by the mother of Lee Scoresby. In 1997, John Parry used it to summon Scoresby, as he required the other man's assistance in locating the bearer of the Subtle Knife. Parry ultimately aimed to unite Lord Asriel and the knife to ensure Asriel's victory in the war against the Authority, but was unaware that the bearer at the time was his own son, Will Parry. 
The ring was of a Navajo design and was both silver and turquoise in colour. The metal was folded over more closely at the corner where a part of the stone had chipped, although this chip had also been worn smooth after Scoresby had run his fingers over it so many times in his youth.