People reported that the ring appears to be London jeweler Jessica McCormack’s 5.02 carat east-west cushion diamond button back ... to be a 5-carat old mine cut, set east-west in grey or black ...

The jeweller describes the ring as being 'a button back ring with a 5.02 carat east-west cushion diamond ... wore appears to be a 5-carat old mine cut, set east-west in grey or black gold on ...