Mary Cooper's grandmother

This unnamed woman was the grandmother of Mary Cooper and thus the great-grandmother of Sheldon Cooper, George Cooper Jr. and Missy Cooper.

She is mentioned in "The Matrimonial Momentum" when Sheldon calls his mother to tell her that Amy broke up with him. It turns out she owned a ring that Sheldon was intending to propose to Amy with. Mary tells Sheldon that he should not give her grandmother's engagement ring back yet since Missy is married and Mary will not let George Jr. give the ring to the whore he's dating.