First, superlatively-soft cashmere was a luxury. Then it became work-a-day, more ubiquitous and affordable than ever thanks to high street behemoths such as Uniqlo and Marks & Spencer. Now, the best cashmere is another desirable cog in fashion’s mighty machine, under closer scrutiny than ever as over-grazing in Mongolia, the world’s cashmere capital, decimates the landscape and manufacturers seek to pull all manners of wools together in a blend that feels swaddling-soft yet is anything but sustainable. How to discern which fibres are of high-quality, and more importantly, are farmed sustainably? There’s no easy answer. But looking into the provenance of fibres, scanning brands’ websites for information on supply chains – Stella McCartney, for instance, uses Re.Verso™ regenerated cashmere made from post-factory cashmere waste in Italy – and making sure your cashmere is truly an investment that can be passed on to future generations are all good places to start. With that in mind, swot up on Vogue‘s tips on how to care for your cashmere, and shop the best timeless pieces here.