Meissen porcelain further precaution, very few workers knew the special secret ("arcanum") of how to make porcelain, and then perhaps only part of the process. Thus, for a few years, Meissen retained its monopoly on the production of hard-paste porcelain in Europe. By 1717, however, a competing production was set up at Vienna, as Samuel Stöltzel sold the secret recipe, which involved the use of kaolin, also known as china clay. By 1760 about thirty porcelain manufacturers were operating in Europe, most of them, however, producing frit based soft-paste porcelain. In order to identify the original Meissen products, Meissen developed markings that
Coalport porcelain a maroon glaze and brought the Nantgarw technical recipes to Rose at Coalport. Coalport and Coalbrookdale specialised in dinner services. The familiar "Indian tree" pattern, which is based in fact on Chinese rather than Indian prototypes, was originated at Coalport; variants have been produced by virtually all the British manufacturers of table wares and continue to be available today. Models that originated at Meissen and Sèvres were copied at Coalbrookdale in the mid-19th century, sometimes with misleading marks, "a practice which ought to have been avoided", William Chaffers observed. Sprigged floral encrusted decoration was also typical of Coalport wares, such