| Clue | Source | Date |
|---|---|---|
| Fictional resource that is, true to its name, very difficult to acquire | ||
| Impossible-to-procure solution to a thorny problem | Wall Street Journal | 21 Sep 2023 |
| Mined compound in the 'Avatar' universe | New York Times | 03 Feb 2023 |
| *“Avatar” | Wall Street Journal | 03 Feb 2021 |