When a character finds a chemical, he/she must make a dice roll using his/her Science (including Chemistry/other relevant specialisms) + PE to recognise it.
If the dice roll is successful, the referee should tell the player what the chemical is and describe its properties. If the dice roll fails, the referee should simply describe to the player what the character sees or smells.
The difficulty depends on how common the chemical is:
| Rarity | Difficulty value |
| Common (e.g. alcohol, common poisons) | 2 |
| Uncommon (e.g. methane) | 6 |
| Rare (e.g. universal solvent) | 10 |
| Very rare (e.g. a chemical or poison the referee has invented) | 14 |