Extremely Rare Stoneware "PRUSSIAN BLUE" Jar, attributed to Branch Green, Philadelphia, PA origin, circa 1825, ovoid jar with footed base, tooled shoulder, and narrow, rounded mouth, the shoulder featuring the words, "PRUSSIAN BLUE.," stenciled in cobalt slip. Prussian blue is a pigment used heavily in oil paints and inks, its name still used by paint manufacturers to this day. The pigment was probably first developed in Berlin in 1706 and quickly becoming popular throughout Europe. Important to art history, Prussian blue was the first stable and essentially lightfast blue pigment to be used since Egyptian blue, which was developed in ancient Egypt but lost after the fall of the Roman Empire. Prussian blue became a cheaper, and therefore widely-used, alternative to indigo and ultramarine, the latter expensively made from lapis lazuli. It also has some medicinal applications. Presumably made for use in an apothecary or general store, this jar is the first example of its kind that we have seen from Philadelphia. Excellent condition with shallow chipping around base. H 12 1/2".