Cobalt blue (CoAl 2O 4) was first described in 1777; it is extremely stable and has been traditionally used as a coloring agent in ceramics.[11][12][13][1] Ultramarine (Na 7Al 6Si 6O 24S 3) was made by grinding the forbiddingly expensive lapis lazuli into a powder until a cheaper synthetic form was invented in 1826 by the French industrialist Jean Baptiste Guimet and in 1828 by and by the German chemist Christian Gmelin.[14] Prussian blue (Fe 4[Fe(CN) 6] 3) was first described by the German polymath Johann Leonhard Frisch and the president of the Prussian Academy of Sciences, Gottfried Wilhelm Leibniz in 1708.[15][16] Azurite (Cu 3(CO 3) 2(OH) 2) is a soft, deep-blue copper mineral produced by weathering copper ore deposits; it was used since ancient times and was first recorded by the first century Roman writer Pliny the Elder.[17] Phthalocyanine Blue BN was first prepared in 1927 and has wide range of applications.