Silestone can cost anywhere from $50 up to $100 per square foot. It all depends on how thick you need the countertop to be, the color and pattern you choose and the dealer that you buy it from. Just to give you a rough estimate of the cost for a countertop, here is an average price for a 54 square foot counter. Material price – $2,465 – $3,474. Cost of installation $165 – $280. Related: Step by step guide to making a detailed estimate for your own kitchen.