Alkaline glaze is a mix of clay and ash or lime that acts as a flux. Cinda K. Baldwin, in her book “Great and Noble Jar,” notes that the earliest glazes found in the Edgefield area were a light yellow-green or gray-green, as seen on this jar, whereas darker green colors tend to be found on later wares.
John Landrum’s factory was the earliest in a long line of potteries established in the area of Shaw’s Creek, south of the town of Edgefield. He was one of three brothers–John, Abner, and Amos–who were pivotal in the early production of stoneware in South Carolina, but perhaps more importantly, in the development of the alkaline-glaze tradition in America. By the second quarter of the nineteenth-century, the brothers’ pottery factories were operated largely by slave labor.
Baldwin, Cinda K. “Great and Noble Jar.” Athens, GA: UGA Press, 1993.