by Kayla Marciniszyn – CART Assistant Lab Director and Collections Assistant
Ceramics provide an effective means of dating historical sites or a particular soil layer because stylistic elements change over time. There are certain wares and decorative techniques that have very specific date ranges that archaeologists can utilize when dating a site if other non-diagnostic artifacts are present. While there are dozens of known types and wares, white refined earthenwares are often prevalent on American sites and can be categorized into three basic ware types: creamware, pearlware, and whiteware. All three have specific production date ranges as well as varying stylistic elements that can help us further refine those dates.
Creamware, the earliest of the three, was formally introduced in England by Josiah Wedgewood in 1762. Cream-colored wares were being produced as early as the 1740s, but Wedgewood succeeded in creating a more refined ware. Wedgewood coined this ware as “Queen’s Ware” after completing his commission for Queen Charlotte in 1765 (Wedgewood Museum 2016). The creamy color seen in the glaze is achieved by the addition of copper to a lead oxide glaze. In places where the glaze pools, such as a footring, the glaze will look almost green. The popularity of creamware began to decline around 1800 with the introduction of pearlware and is virtually non-existent after 1820.
English potters experimented different techniques in order to achieve a ceramic that could achieve the glass-like appearance of Chinese porcelain. It was discovered that by adding cobalt to a lead oxide glaze potters could achieve the blue-tinted glaze found on early Chinese porcelains. This ware goes by a few different names including pearl white, China glaze, and pearlware. China glaze appears as early as 1775 but Josiah Wedgewood introduced his “pearl white” wares in 1779 (Miller and Hunter 2016). We usually refer to any ceramics with the blue-tinted glaze as “pearlware,” an adaptation of Wedgewood’s “pearl white,” but some may refer to pearlwares with a Chinese-style decoration as “China glaze.”
Over time the use of cobalt decreased, most likely due to the expense of obtaining the mineral. Fun fact: the word cobalt is derived from the German word “kobalt,” which means “goblin.” Cobalt ore, when smelted, produces a powder that contains arsenic, which is highly toxic. As the use of cobalt decreased, whiteware begins to emerge, approximately around 1820. During the transition between pearlware and whiteware, it can sometimes be difficult to determine the difference between the two. Early whitewares can have a slight blue hue to the glaze, particularly in areas where the glaze is thicker. Sometimes we define this as transitional whiteware. Whitewares are still produced today.
So, when identifying white refined earthenwares look at the color of the glaze! Sometimes it is helpful to set the ceramic sherd on a white piece of paper. Whitewares will blend in with the paper but creamware and pearlware should stand out.
Wedgewood Museum. 2016. “Queen’s Ware.” Accessed February 16, 2017. http://www.wedgwoodmuseum.org.uk/learning/discovery-packs/pack/lives-of-the-wedgwoods/chapter/queens-ware
Miller, G. and Hunter, R. 2016. “How Creamware Got the Blues: The Origins of China Glaze and Pearlware.” Accessed February 16, 2017. http://www.chipstone.org/html/publications/CIA/2001/MillerHunter/MillHuntIndex.html
Jefferson Patterson Park Mac Lab. “The Evolution of Creamware, Pearlware and Whiteware.” http://www.jefpat.org/diagnostic/Post-Colonial%20Ceramics/Shell%20Edged%20Wares/Shell%20Edged%20Wares%202nd%20page.htm
Seidel, J. 1990. ““China Glaze” Wares on Sites from the American Revolution: Pearlware Before Wedgewood?” Historical Archaeology 24 (1): 82-95. Ceramics in the image are listed from left to right: creamware, pearlware, and whiteware