final jasperware, and little was sold. Jasperware's composition varies but according to one 19th-century analysis it was approximately: 57% barium sulphate, 29% ball clay, 10% flint, 4% barium carbonate. Barium sulphate ("cawk" or "heavy-spar") was a fluxing agent and obtainable as a by-product of lead mining in nearby Derbyshire. The fired body is naturally white but usually stained with metallic oxide colors; its most common shade is pale blue, but dark blue, lilac, sage green (described as "sea-green" by Wedgwood), black, and yellow are also used, with sage green due to chromium oxide, blue to cobalt oxide, and lilac to manganese oxide, with yellow probably coming from a salt of antimony, and black from iron oxide. Other colours sometimes appear, including white used as the main body colour, with applied reliefs in one of the other colours. The yellow is rare. A few pieces, mostly the larger ones like vases, use several colours together, and some pieces mix jasperware and other types together. The earliest jasper was stained throughout, which is known as "solid," but before long most items were coloured only on the surface; these are known as "dipped" or "dip". Dipping was first used in 1777, Wedgwood writing that "the Cobalt @ 36s. per lb, which being too dear to mix with the clay of the whole grounds". By 1829 production in jasper had virtually ceased, but in 1844 production resumed making dipped wares. Solid jasper was not manufactured again until 1860. Early dark blue was often made by dipping a body made from the solid light blue. In the best early pieces the relief work was gone over, including some undercutting, by lapidaries. Wedgwood colours Wedgwood designs The artists used for jasperware cannot always be identified, as they are not named on pieces they designed. As well as the Flaxmans, father and son, Wedgwood commissioned George Stubbs, and William Wood. William Hackwood was his chief in-house modeller, who was sometimes allowed to initial pieces. Using the celebrity of the aristocratic amateurs Lady Templeton and Lady Diana Beauclerk, as well as Emma Crewe, no doubt helped sales. As well as many original designs, ancient and modern works in various media were copied. Jasperware is particularly associated with the neoclassical sculptor and designer John Flaxman Jr who began to supply Wedgwood with designs from 1775. Flaxman mostly worked in wax when designing for Wedgwood. The designs were then cast: