Various strains will sometimes have different colored hairs, or pistils. Typically most do become kind of orange-ish. But some look, more red, some maybe more yellow, and some even a pinkish or purple.
Strains from the Hindu Kush often have some of the reddest hairs. They are the ones that look magenta or pink when fresh, before they start to brown and then look more reddish brown.
You had mentioned brown weed before, carotenoid pigments in some strains are responsible for the yellow, orange, red, and brown colors in the leaves and other tissue like the stems, branches and petioles. Anthocyanin is responsible for the purple pigments and is found more in strains with Hindu Kush or Colombian ancestry. But enough anthocyanin is found in all cannabis that all will turn purple-ish if it gets cold night temperatures during the end of flowering.
~MacG