Are there any drugs that kids call black?

Answer 1

Black more often than not will refer to Heroin, White can refer to White sometimes opium, whereas red usually refers to Opium

green is usually cannabis

combinations of colors usually reflect some sort of pharmaceutical

other color usages are uncommon if they exist at all...

as for black being used for cannabis I have never heard it used it called just 'black' but I have heard a specific strain referred to as 'black ___'