Murex purple pigment has a historical, cultural and aesthetic value.

Purple from Murex trunculus is dibromoindigo. Murex is a symbol color purple; dibromoindigotin shown on this page (imperial purple, with more pink and less indigo blue to the blue jean dye).

Artistic source and more.

Imperial purple acquired a word-of-mouth following and remains an extraordinary dibromo-indigo color to this day.