How to make sure you buy 100% pure cashmere product?

Generally when you go to many high street stores or supermarkets or most of web shops, you will find items marked as cashmere. Look at the labels to find out how much % of cashmere or pashmina is there in that product. Sometimes its just 10-20% of cashmere. There is no use of buying such product if you want to feel touch of pure cashmere. Some sell 70% pashmina and 30% silk to reduce price. Make sure how much pashmina or cashmere is present in product before you buy. If you want to buy something which keeps you warm in winter and which is very soft then go for 100% Pure Cashmere.