The purple-purple coloration is a result of the absorption by The larger particles while the eco-friendly coloration is attributed to The sunshine scattering by colloidal dispersions of Ag nanoparticles with a sizing > 40 nm. The Lycurgus cup is acknowledged as among the oldest artificial nanomaterials [1]. The same result https://www.directivepublications.org/journal-of-applied-nanoscience/