Looking at this the answer looks lilke Orcein- you look at the above link + tell me what you think.
Must have lunch now- hands are shaking with hunger!
Warm wishes, Bea ;-)
Actually, think it is Orchil :-)
Too hungry to think;-). Good luck Aquagility + hope you win something soon as you have helped me out on numerous occassions :-)!
Warm wishes, a very hungry Bea
Sorry aquagillity- it was on absoloute astronomy. Sorry the link did not work. Did try for you.
Wonder if this helps:- http://en.wikipedia.org/wiki/Orchil
Gosh, hope it will all be clear for you soon as want you to have the right answer with a good explanation of why very soon. Rollo is a genius so methinks his words must be right. Warm wishes, Bea :-)
..and orcein is a purple dyestuff obtained from orcinol which is also obtained from lichens - Chambers as well.
I would probably go for orchil, only because when Googled with "litmus" it gets more hits than orcein.