| # | Clue | Answer As Given | Value | Round | Category | Air Date | Show |
|---|---|---|---|---|---|---|---|
| It's the "I" in ROYGBIV, a mnemonic for the colors of the visible spectrum | indigo | $600 | J | THE COLORS OF SCIENCE | 2023-01-16 | #8786 | |
| This plant is no longer widely grown to produce blue dye since the dye can be made synthetically | indigo | $800 | DJ | SCIENCE | 1987-12-07 | #751 |