Wiktionary
anthrapurpurin
n. (context organic compound English) 1,2,7-trihydroxyanthraquinone, a purple dye used in histology for the detection of calcium
Wikipedia
Anthrapurpurin
Anthrapurpurin, or 1,2,7-trihdroxyanthraquinone, is a purple dye used in histology for the detection of calcium.