nut-brown 
adjective
Of a rich dark brown colour: a nut-brown face...
- A slender adult leader with raven hair and glistening alabaster skin which reflected the full moon's light was playing a set of rich, nut-brown pipes.
- Renee's normally cobweb-like cloud of wavy brown hair now fell in a straight, gleaming sheen all the way to her upper back, at last looking more nut-brown than it did mousy.
- The face of a young girl, only sixteen, with nut-brown hair and hazel eyes appeared in the clouded liquid.