Pottery

Pottery is the process of forming vessels and other objects with clay and other ceramic materials, which are fired at high temperatures to give them a hard, durable form. Major types include earthenware, stoneware and porcelain. The place where such wares are made by a potter is also called a pottery (plural 'potteries'). The definition of pottery used by the American Society for Testing and Materials (ASTM), is 'all fired ceramic wares that contain clay when formed, except technical, structural, and refractory products.' In archaeology, especially of ancient and prehistoric periods, 'pottery' often means vessels only, and figures etc. of the same material are called 'terracottas'. Clay as a part of the materials used is required by some definitions of pottery, but this is dubious.pots are positioned on and amid the branches and then grass is piled high to complete the mound. Although the mound contains the pots of many women, who are related through their husbands' extended families, each women is responsible for her own or her immediate family's pots within the mound. Pottery is the process of forming vessels and other objects with clay and other ceramic materials, which are fired at high temperatures to give them a hard, durable form. Major types include earthenware, stoneware and porcelain. The place where such wares are made by a potter is also called a pottery (plural 'potteries'). The definition of pottery used by the American Society for Testing and Materials (ASTM), is 'all fired ceramic wares that contain clay when formed, except technical, structural, and refractory products.' In archaeology, especially of ancient and prehistoric periods, 'pottery' often means vessels only, and figures etc. of the same material are called 'terracottas'. Clay as a part of the materials used is required by some definitions of pottery, but this is dubious. Pottery is one of the oldest human inventions, originating before the Neolithic period, with ceramic objects like the Gravettian culture Venus of Dolní Věstonice figurine discovered in the Czech Republic dating back to 29,000–25,000 BC, and pottery vessels that were discovered in Jiangxi, China, which date back to 18,000 BC. Early Neolithic pottery artefacts have been found in places such as Jōmon Japan (10,500 BC), the Russian Far East (14,000 BC), Sub-Saharan Africa and South America. Pottery is made by forming a ceramic (often clay) body into objects of a desired shape and heating them to high temperatures (1000-1600 °C) in a kiln and induces reactions that lead to permanent changes including increasing the strength and solidity of the object's shape. Much pottery is purely utilitarian, but much can also be regarded as ceramic art. A clay body can be decorated before or after firing. Clay-based pottery can be divided into three main groups: earthenware, stoneware and porcelain. These require increasingly more specific clay material, and increasingly higher firing temperatures. All three are made in glazed and unglazed varieties, for different purposes. All may also be decorated by various techniques. In many examples the group a piece belongs to is immediately visually apparent, but this is not always the case. The fritware of the Islamic world does not use clay, so technically falls outside these groups. Historic pottery of all these types is often grouped as either 'fine' wares, relatively expensive and well-made, and following the aesthetic taste of the culture concerned, or alternatively 'coarse', 'popular' 'folk' or 'village' wares, mostly undecorated, or simply so, and often less well-made. All the earliest forms of pottery were made from clays that were fired at low temperatures, initially in pit-fires or in open bonfires. They were hand formed and undecorated. Earthenware can be fired as low as 600 °C, and is normally fired below 1200 °C. Because unglazed biscuit earthenware is porous, it has limited utility for the storage of liquids, and even eating off. However, earthenware has a continuous history from the Neolithic period to today. It can be made from a wide variety of clays, some of which fire to a buff, brown or black colour, with iron in the constituent minerals resulting in a reddish-brown. Reddish coloured varieties are called terracotta, especially when unglazed or used for sculpture. The development of ceramic glaze which makes it impermeable makes it a popular and practical form of pottery. The addition of decoration has evolved throughout its history. Stoneware is pottery that has been fired in a kiln at a relatively high temperature, from about 1,100 °C to 1,200 °C, and is stronger and non-porous to liquids. The Chinese, who developed stoneware very early on, classify this together with porcelain as high-fired wares. In contrast, stoneware could only be produced in Europe from the late Middle Ages, as European kilns were less efficient, and the right sorts of clay less common. It remained a speciality of Germany until the Renaissance.