The term 'curling stone' is a type of stone used in the sport of curling. The stone is typically made of GRANITE, which is a type of rock composed of interlocking crystals of quartz, feldspar, and mica. Curling stones are typically round and flat, with a handle on top, and are made from a special type of GRANITE that is quarried in Scotland. The GRANITE is cut into discs and then polished to create the curling stone.