Thanks for all the marvellous guesses! You have come up with things I haven't experimented with yet, but would now like to! Here is the list so far, with guesses from yesterday added:
pink or rose clay
Okay, I will give you number 1, which most of you guessed - Pink Clay.
Today's Clue: Soap Number 2 is coloured with a root. Soap Number 3 is coloured with 2 roots. Soap number 4 is coloured with a clay.