Mineral Fibers: Asbestos, Tinsel, and other metallic fibers.
Remanufactured Material: Noils, Mungo, Shoddy, Extract, and Flocks.
Artificial Fibers: Spun Glass, Artificial Silk, and Slag Wool.
The Structure of Wool. A large part of the people of the world have always used wool for their clothing. Wool is the soft, curly covering which forms the fleecy coat of the sheep and similar animals, such as the goat and alpaca. Wool fiber when viewed under the microscope is seen to consist roughly of three parts:
1st. Epidermis, or outer surface, which is a series of scales lying one upon the other.
2d. Cortex, or intermediate substance, consisting of angular, elongated cells, which give strength to the wool.
3d. Medulla, or pith of the fiber.
WOOL FIBER
Highly magnified
Difference between Wool and Hair. Not all animal fibers are alike. They vary in fineness, softness, length, and strength, from the finest Merino wool to the rigid bristles of the wild boar. At just what point it can be said that the animal fiber ceases to be wool and becomes hair, is difficult to determine, because there is a gradual and imperceptible gradation from wool to hair.[1] The distinction between wool and hair lies chiefly in the great fineness, softness, and wavy delicacy of the woolen fiber, combined with its highly serrated surface—upon which the luster of the wool depends.