The original chamois cloths were made not from sheepskin, but from the skin of the chamois, a large sized mountain goat, native to the European mountains. When chamois became nearly extinct, chamois cloths began to be made using sheepskin, which proved to be better than the original chamois skins.
Sheep skin has a naturally open fiber structure and is also slightly hydrophilic or absorbent, the only skin in the world with this property. The absorption capabilities are significantly further enhanced by the marine oil effect on the protein chain that allows the tanned leather to absorb and retain large amounts of water. The loose weave of the fiber in the leather allows the cloth to hold an average of 5 times its own weight in water, while retaining the ability to be easily rinsed and wrung out.
After the grain has been removed from the skin, the tanning oils are infused into the skin. The Tanning Process for a chamois cloth, like any other tanning, is fundamentally a process whereby a raw protein material, the sheepskin pelt, is chemically modified and preserved. In the process of preservation, the skin can be given, within the limitations of its chemical structure, certain characteristics. The protein structure of sheepskin, when tanned with fish oil, produces an extremely soft, durable and highly water absorbent material. When tanned properly, its long protein chain is transformed from a flat, tight, linear, water neutral fiber to a multi-dimensional, spongy, more open, water absorbent material. This gives chamois cloths the softness, absorbency and durability for which they are so well known.
Due to the marine oils used in the tanning process, a genuine leather chamois will have a slight fish oil smell and will also fade if left in direct sunlight, making counterfeits and synthetics reasonably easy to distinguish from the genuine article. Natural leather chamois are also made from a renewable resource, where synthetics are petroleum based products and are not.