The artist Sir Anthony van Dyck spent his life illustrating the English royalty in the early to mid-17th century, and during his career he became famous for his relaxed elegance and use of a particular hue of brown. The brown pigment would eventually be named after him, ‘van Dyck brown’, and can still be found today. However, another pigment became commercially available much later after his death, and it is commercially available as ‘van Dyck crystals’. In practice the two terms are used interchangeably, as they both are made from organic material. Here we investigate the complex chemical composition of ‘van Dyck crystals’, and we show that the two pigments are distinctly different, both in composition and in origin. We show that the colored component of the ‘van Dyck crystals’ is not crystalline and should not be confused with the original pigment. © 2020 Elsevier Ltd