oolith

Borrowed from Late Latin oolithus; the Latin word was coined by the German doctor and mineralogist Franz Ernst Brückmann (1697–1753) as a translation of German Rogenstein (“oolite”) (Rogen (“fish roe”) + Stein (“stone”)). Oolithus is derived from Ancient Greek ᾠόν (ōión, “egg; seed”) (possibly ultimately from Proto-Indo-European *h₂ew- (“to clothe oneself, dress; to be dressed”), in the sense of a bird being clothed in feathers) + λῐ́θος (lĭ́thos, “a stone; stone as a substance”) (see further at that entry), analysable as oo- +‎ -lith.