Especially flavorful cheese made from goat’s or cow’s milk. The mass of fresh cheese is strained through muslin, then placed between heavy flat stones whose weight squeezes out any remaining liquid. (The cheese’s name is derived from the Greek word for stone, petra.) On Tinos, this is done in a special marble jar with a spout and lid to facilitate the process. The cheese, in its final disc shape, is consumed raw but is also used as the basis for making other cheeses like malachto, volaki, sklavotyri, or kopanisti.