I'm sure you've all come across the Mori Bokhara and Jaldar rugs and the Pak-Persian designs using a silk like wool that they sometimes call "silk-touch".

Does anyone actually know what the material actually is?

I thought viscose/rayon but what made me doubt it is a couple of years ago when the guy who provided the rug cleaning training and equipment was in I asked him what he thought it was and he said it was wool. In fact he said it was a good wool. Which is worrying... I was never convinced. Although saying that I don't think it's 100% viscose, it's not like the art-silk type rugs but it's not like wool either. Perhaps the ones we have are blends or something.

Next logical question would be... why?

Why do people go to all that effort of knotting a rug only to make it out of sub-standard materials? It's the same with the silk rugs (although I'm sure the price difference between viscose and silk is a lot more than between wool and viscose or rayon). It just seems like madness... like painstakingly carving handmade furniture but using MDF.