Wool is the natural protein fiber grown by sheep and certain other mammals, composed primarily of the protein keratin. Its unique crimped structure creates millions of air pockets that provide exceptional thermal insulation, making wool one of nature's most effective temperature regulators.
Sheep Wool and Merino
Standard sheep wool comes from hundreds of breeds with fiber diameters ranging from 20 to over 40 microns. Coarser wools are used for carpets, upholstery, and industrial felts, while finer wools go into apparel. Merino wool, sourced from Merino sheep originally bred in Spain, represents the premium tier of apparel wool. Merino fiber diameter typically ranges from 15 to 25 microns, with the finest ultrafine Merino measuring as low as 11.5 microns. For comparison, a human hair averages 50 to 100 microns in diameter.
The fineness of Merino wool eliminates the prickling sensation associated with coarser wool against bare skin. The fibers also have a natural crimp of up to 30 waves per inch, creating loft that traps warm air while maintaining breathability. Merino can absorb up to 35 percent of its own weight in moisture vapor without feeling wet, actively regulating humidity against the skin.
Cashmere
Cashmere comes from the soft undercoat of the Capra hircus goat, which inhabits the high plateaus of Inner Mongolia, China, Mongolia, Iran, and Afghanistan. Each goat produces only 100 to 150 grams of usable cashmere fiber per year after the coarse outer guard hairs are separated. Cashmere fiber diameter ranges from 14 to 19 microns, making it finer than all but the most premium Merino wool.
The extreme cold of the goats' native habitat drives the development of this ultra-fine insulating undercoat. Cashmere is 6 to 8 times warmer than sheep wool by weight yet notably lighter and softer. The fiber scales on cashmere are shorter and fewer than on sheep wool, giving it a distinctive smooth, silky hand feel with minimal itch. However, cashmere is more delicate than wool, with lower tensile strength and greater susceptibility to pilling and abrasion.
Lanolin and Natural Properties
Raw sheep wool contains lanolin, a waxy substance secreted by the sheep's sebaceous glands that waterproofs the fleece. Lanolin comprises 5 to 25 percent of raw wool weight depending on breed. During scouring, lanolin is removed and refined for use in cosmetics, pharmaceuticals, and industrial lubricants. The removal of lanolin makes the wool absorbent and dyeable.
Wool is naturally flame resistant due to its high nitrogen content (approximately 16 percent) and high moisture content, igniting at around 600 degrees Celsius versus roughly 250 degrees Celsius for cotton. It is self-extinguishing when removed from flame. Wool resists odors, sheds dirt due to its scaly surface structure, and is biodegradable. However, wool is susceptible to moth damage and requires care in washing to prevent felting and shrinkage.
Global Production
Global wool production totals approximately 1.2 million tonnes of greasy wool annually (2022 data). Australia is the dominant producer, accounting for about 25 percent of global wool output and a much larger share of fine Merino wool exports. China ranks second in total production and is also the world's largest wool processor and importer. New Zealand is the third-largest producer, known primarily for crossbred wools used in carpets and interior textiles. Together, Australia, China, and New Zealand produce over 50 percent of the world's wool.
Cashmere production is concentrated in China, which accounts for roughly 70 percent of global output, primarily from Inner Mongolia. Mongolia follows as the second-largest producer with about 20 percent. Total annual global cashmere production is estimated at 25,000 to 30,000 tonnes of raw fiber, a tiny fraction compared to sheep wool, underscoring cashmere's status as a luxury material.