Stoneware was once an almost universal material in American homes. The versatile, nonporous ceramic made ideal containers of all kinds, including the ubiquitous stoneware crock. Stoneware is made of grey and tan clays fired to a high temperature. As there were few American producers prior to 1800, most existing antique stoneware crocks date from the 19th century.
Look for a glassy appearance on the surface of the crock. The glassy look is the result of a process called vitrification, in which the clays turn into a material that has properties similar to glass.
Feel the surface of the crock. Part of the process of glazing antique stoneware involved throwing handfuls of salt at the vessel. The technique left an uneven, pebble-like surface.
Observe the shape of the vessel. Genuine antique stoneware crocks resemble the kinds of pots used to make baked beans. Taller pots tend to be widest in the middle, with often prominent lips. Shorter pots will usually be of even diameter with no pronounced lip.
Look for indications of freehand decoration in cobalt blue, purple or brown. Designs are generally simple, and in the traditions of folk art. Many antique stoneware crocks also bear the names of merchants and geographic locations. The lettering follows the same colour scheme as other decoration.
Examine the way in which the simple picture and letters were created. Painting was normally performed with a blunt-pointed instrument.
Many antique stoneware crock designs are almost abstract in appearance, and take the form of squiggly lines or broad strokes.
Beware of precise, evenly drawn designs. Lettering should be either freehand or at least hand-stencilled.