The pottery of coloured glazes decoration over unglazed earthenware molded in low relief. Terracotta is the term used for unglazed earthenware, and for ceramic sculpture made in it. Occasionally versions are seen with a glazed china front and an unglazed stoneware back. Both glazed and unglazed ceramic jars can be used. The brick pattern was Flemish bond brickwork with dark glazed headers and unglazed stretchers. Reddish coloured varieties are called terracotta, especially when unglazed or used for sculpture. Made of unglazed stoneware, the "Julleuchter" was decorated with early pagan Germanic symbols. Parian dolls were made in Germany of white unglazed porcelain from the 1850s onwards. When rubbed against unglazed porcelain, true jet will leave a chocolate brown streak. Unglazed bisque dolls became popular after 1850. All three are made in glazed and unglazed varieties, for different purposes. It was notable for Neoclassical subjects and styles, and figures in unglazed biscuit porcelain. On the Mohs scale, a streak plate (unglazed porcelain) has a hardness of approximately 7.0. It is also an unglazed burnished ware. The combustible material results in smoke, which stains the unglazed portions of the pottery black.