An apparent Good Samaritan stole the rings from the fingers of an 84-year-old woman who had fallen, police said.
The man, who was walking a small dog, helped her to her feet after the fall in Kings Heath, Birmingham.
West Midlands Police said he then roughly took the jewellery from her hands, including her wedding and engagement rings, ignoring her pleas to stop.
The woman was left with bruised arms and in an "extremely distressed state".
An eternity ring and Claddagh ring - a piece of traditional Irish jewellery - were stolen during the attack in Portman Road on 8 September,
The man is described as white and in his mid-20s.