An ink-stone is a stone for the grinding and containment of ink. Traditional Chinese ink was usually solidified into sticks for easier transport and preservation. Even a small amount of water could be applied to the end of an ink stick, and that end would be ground with the flat surface of the ink stone.

An ink stone will affect the quality and texture of the ink that is ground upon it. Four kinds of ink stones are especially noted in ink-stone art history and are popularly known as the Four Famous Ink stones. They are Duanshi stone from Duanxi, Guangdong Province, She stone from She County, Anhui Province, Tao River stone from South Gansu Province and Chengni ceramic stone from Luoyang, Henan Province.

The ink-stone, together with the ink brush, ink (stick) and paper, are the four writing implements traditionally known as the Four Treasures of the Study.