Kozoite-(Nd), Nd(CO3)(OH), occurs in cavities and fissures of alkali olivine basalt exposed at Niikoba, Hizen-cho, Higashi Matsuura-gun, Saga Prefecture, Japan, in association with lanthanite-(Nd) and kimuraite-(Y). The crystal structure was refined by the Rietveld method in space group Pmcn; a = 4.9829(1), b = 8.5188(2), c = 7.2570(2) Å, Z = 4 using powder diffraction data obtained by a combination of a Gandolfi camera and monochromatic synchrotron radiation. Kozoite-(Nd) is pale pinkish-purple to white with a vitreous to powdery luster. The calculated density is 4.77 g/cm3. It has high birefringence, α = 1.698(2), α = 1.780(5). The four strongest lines in the X-ray powder patterns [d(Å), I/I0, hkl] are (4.29, 100, 110); (2.93, 89, 102); (2.33, 78, 131) and (2.06, 78, 221). Kozoite-(Nd) is the first naturally occurring RE(CO3)(OH) end-member in the ancylite group.