Ply and gauge are terms used to describe the way a jumper is knitted: it does not refer to the quality or value of the sweater.
As cashmere is a precious and rare commodity, the weight of cashmere used in a jumper directly determines its value.
The higher the percentage of cashmere used, the higher the value.
And that's why 100% cashmere is always more expensive and than cashmere blends.
And, that's why heavier cashmere knits are always more pricey than lighter weight knits.
When investing in a cashmere sweater, make sure that you buy top-grade Inner Mongolian cashmere which has not be interbred with coarser haired goats: this type of cashmere is rough to the touch.
In order to meet high international demand for cashmere, a lot of herdsmen have interbred their cashmere goats with coarser haired goats to produce more yarn.
However, such yarn is both shorter and rougher.
The longer and thinner the fibre, the softer and more longer lasting the piece.
A top grade 100% cashmere sweater should last a lifetime if looked after properly.