This two-gallon crock is an example of mid-19th-century salt-glazed stoneware. Salt glazing is a process where pots are fired with sodium vapors and salt is inserted into the kiln at 2,000 degrees, releasing sodium, which acts as a flux on the silica in the pots. This action creates a very hard, transparent and waterproof glaze. Crocks like these were mainly used for making sauerkraut, a dietary staple of many European immigrants, but until the arrival of cheaper machine made molded glass jars, crocks and jugs were also used for the storage of everything from pickles to kerosene. Examples like this one and generally came with a lid, which is now seldom found with them.
Values for them depend a great deal on the their maker, vintage, quality and quantity of decoration and current condition. Damaged examples with cracks do tend to sell for less than undamaged pieces. The most sought after crocks are those with hand decorated cobalt blue decoration and stamped by their maker, which can sell in the five figures, but more average examples like this one tend to sell in the $200.00- $400.00 range.