Cashmere yarn is today well know for its peculiarity : softness, warmth, comfort. But there is cashmere and cashmere, as for the wine. Talking about Italian red wine doesn't mean that is for sure a good one, just because it is Italian.
One thing is worth to know it is that a soft hand at the moment of the purchasing is not necessarly meaning high quality. There are several ways of washing the cashmere in order to obtain a softer hand, but if the quality of cashmere is not good, the hand will be very good, but the strength of the fiber will be compromised.
Washing the cashmere during a process called "follatura" it is a process producing a softer hand extracting the fiber; it is a kind of "pre-aging" of the thread and of course more this process is taken to extreme, more the fiber is damaged and will stand less time.
So sometime the best quality of cashmere has at the beginning a rougher hand, but in washing the yarn becomes richer and more silkier with each wash and it's standing longer.
Of course there are also different kind of thickness of the cashmere, 2/28.000, 2/58.000 (once more 2/28.000 means there are 28.000 meters of thread in one kilo, twisted in 2 ply) and different kind of knitting..