One of the most valuable natural fibres is cashmere wool, which is obtained from the cashmere goat. The goats live in Mongolia and in the general Himalaya region, they can be found as high up as 5000m. In order to endure the cold at such altitudes, these goats have a very soft undercoat. Once, a year the animals shed their wool and the bundles can be collected. However, after collecting the hair, the fine bottom hair has to be sorted from the rest of the fur. Textiles produced from cashmere are some of the softest ones available. They often have a natural shine and are very light.
You can find more information about Cashmere (WS) in Wikipedia.