Apsley Pellatt was a leading manufacturer of glassworks and responsible for one of the earliest patents for crystallo ceramie in 1819, commonly known as glass sulphides. The process involves fully encasing a porcelain-like material in glass, and the term “sulphide” likely comes from the mold maker's use of sulfur in the 18th and 19th centuries.
The firm was started by Apsley Pellatt Sr. (1763 – 21 January 1826) around 1790 when he purchased Falcon Glass House in Blackfriars. His son joined the firm in 1811 and renamed the firm Apsley Pellatt & Co. in 1826. They were the leading manufacturers of sulphide glass, and examples of their work are preserved in the Victoria and Albert Museum and the Corning Museum of Glass. Similar examples of sulphide portraits of George IV and Queen Victoria are cited in P. Jokelson, Sulphides: The Art of Cameo Incrustation, New York, 1968, p. 6.