Mine is mohair and it dyed fine but it takes several applicatoins with the stove top method. I have applied the dye 4 times already and may still need one more time.
I bought mine new from Stateline Tack for $14.99. Mohair. Dyed it ONCE with Liquid Rit in a pot on the stove, then stretched it on a board with nails to keep it from shrinking once it dried. Left it there to dry for 2 days, and it looks perfect!