This autumn, it pays to pay a little bit more for your knitwear.

“You got to know how I feel about you,” Prince sang on his 1993 track “Pink Cashmere”, “how I always want you near.” At MR PORTER, we share this sentiment. Which is why, come the colder months, or even this transitional season, we like to have the soft touch of cashmere knitwear as close to our person as possible at all times – if not always, necessarily, in pink. But we’ll be the first to admit that this comes at a price.

So what is it that elevates cashmere above the standard wool? To spin this particular yarn, we first have to separate the sheep from the goats. This fine, silky fibre, as the name suggests, comes from cashmere goats, a breed native to the disputed Kashmir region of the Indian subcontinent (perhaps, then, we should be quoting Led Zeppelin instead of Prince?), but now found across the Asian landmass – although not abundantly so. The relative scarcity of this fleece is one factor behind its cost: a mere 6,500 tonnes of pure cashmere is produced globally each year.

As with many things today, China is currently the world’s leading supplier (it produces more than 70 per cent of all cashmere wool), but it is the output of its autonomous Inner Mongolia region that is the most prized. It’s here that the high-end brands associated with the very finest knitwear – notably Loro Piana, Brunello Cucinelli and Ermenegildo Zegna – source their wool.

To survive in the harsh conditions of this remote and unyielding wilderness, natural selection has led the cashmere goat to embrace layering of a sort. Each goat has two coats – a top coat of bulky hair and what you could call a base layer of short, fine and extremely insulating hair known as a duvet. It’s only the duvet that is used for premium cashmere, delicately teased from the goat during the spring moulting season using a comb to avoid causing the animal any harm. With this method, the average goat produces just 150g of duvet fibre each year, making it a very precious resource indeed.

The hair of the inland Mongolian goats is longer and more resilient than that of its counterparts elsewhere. This makes for wool that is stronger, and less likely to fray or bobble, and produces garments that are pleasingly tactile and light yet incredibly warm.

From the furthest reaches of landlocked Asia to the “Cashmere Valley” of Umbria, where much of Italy’s cashmere production is concentrated. The foremost Italian labels select the finest fibre that is barely 15 microns (a micron being a millionth of a metre) thick. Most of these luxury brands now offer detailed place-of-origin labelling, and put greater emphasis on the lack of bleaching or chemical substances in the production process.

This all makes the relative high cost of cashmere wool actually something of a sign of assurance that you are actually getting a superior, authentic product. In short: don’t let the price of a sweater get your goat.