objet de vertu
/ˌɒbʒeɪ də vəːˈt(j)uː/(also objet de virtu)
noun
An article that is interesting because of its antiquity, beauty, quality of workmanship, etc.
Origin
Mid 19th century; earliest use found in Vanity Fair. From objet + de + vertu, variant of virtu, probably after French objet d'art objet d'art. There is no corresponding phrase in French; the required sense of French vertu does not exist.