“The animal fibers are of protein and the hair fibers usually consist of three parts: a) the outer layer or epidermis called scales, b) the cortex which usually makes up the major portion of the fiber, and c) the medulla, a dark core, oval or round in shape, usually heavily pigmented, which appears commonly in alpaca and llama, occasionally in camel, mohair, vicuna, and some coarse wools, but not in cashmere.” -Fiber Science 211/NCSU/CoT