I was looking up information about makeup brushes when I stumbled upon this great site on make-up tips. Very useful tips they have, and here are some relevant ones I’ve learnt about brushes.
Natural or synthetic brush
Natural bristled brushes are best as they are soft to the touch and are most effective for applying powder blush, face powder, eyeshadow or lipstick. Synthetic brushes, which are much more affordable and are often more durable and harder to damage are best reserved for eyeshadow base, cream eyeshadows, and concealers.