Curling is a sport in which players slide stones across a sheet of ice towards a target area. Two teams, each of four players, take turns sliding heavy, polished granite stones across the ice curling sheet towards the house, a circular target marked on the ice.[1] Each team has eight stones. The purpose is to accumulate the highest score for a game, points being scored for the stones resting closest to the centre of the house at the conclusion of each end, which is completed when both teams have thrown all of their stones. A game may consist of ten or eight ends. High quality curling stones are made from a specific type of granite called "ailsite", found on Ailsa Craig, an island off the Ayrshire coast in Scotland. Ailsite has very low water absorption, which prevents the action of freezing and melting water from eroding the stone. Each stone ways between 38 and 44 pounds.