### Clue: Pigment that's brown or black turning livid round stone (6)
### Answer: BISTRE 
 ### Explanation: Definition: Pigment that's brown
B[lack] + ST in IRE ("turning livid" -not sure about this, but I can just about believe it). Chambers labels the "extremely angry" definition of "livid" as "informal", which I find surprising as this is probably now its most common meaning