Diamandy also developed a passion for archeology, enjoying in particular the books of Gabriel de Mortillet and Theodor Mommsen. He camped out with Nicolae Beldiceanu in Cucuteni, where he helped on the inventory of the Cucuteni-Trypillian culture. Diamandy was also a member of the Bârlad National Romanian Committee, which gathered funds and artifacts for the Romanian delegation to the 1889 Exposition Universelle. He was working on a novel in the manner of Émile Zola, which, according to Gorovei, was over-detailed and boring.