ΔE 18.6, loose: different enough that you should pick on purpose. Sun Ray is noticeably lighter, more saturated than Terminatus Stone.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Sun Ray is noticeably lighter, more saturated than Terminatus Stone.
The same difference applies the other way round: Terminatus Stone is noticeably darker, more muted.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Terminatus Stone on the colour wheel See Sun Ray on the colour wheel
All matches: Terminatus Stone equivalents · Sun Ray equivalents