lanthanite series

{{Infobox mineral | name = Lanthanite-(La), Lanthanite-(Nd), Lanthanite-(Ce) | boxwidth = | boxbgcolor = | image = LanthaniteNd R060993 Sample Photo 10941 M.jpg | imagesize = 260px | alt = | caption = Lanthanite-(Nd) from Mitsukoshi, Hizen-cho, Karatsu City, Saga Prefecture, Japan. | category = Carbonate minerals | formula = (REE)2(CO3)3·8(H2O) | IMAsymbol = Ltn | strunz = 5.CC.25 | dana = (La): 15.04.02.01 (Nd): 15.04.02.02 (Ce): 15.04.02.03 | system = Orthorhombic | class = Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) | symmetry = Pbnb | unit cell = a = 9.476(4)–9.483(6) b = 16.940(8)–16.938(11) c = 8.942(4)–8.965(3) [Å], Z = 4 | molweight = | color = Pale pink to purple | colour = | habit = Platy | twinning = Common on {101} | cleavage = Micaceous, perfect on {101} | fracture = Uneven | tenacity = Sectile | mohs = 2.5 | luster = Vitreous to pearly | streak = White | diaphaneity = | gravity = | density = 2.78–2.84 (measured), 2.79–2.816 (calculated) | polish = | opticalprop = Biaxial (−) | refractive = | birefringence = | pleochroism = | 2V = 58°–61° (measured), 60°–63.5° (calculated) | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = }}

Lanthanites are a group of isostructural rare earth element (REE) carbonate minerals. This group comprises the minerals lanthanite-(La), lanthanite-(Ce), and lanthanite-(Nd). This mineral group has the general chemical formula of (REE)2(CO3)3·8(H2O). Lanthanites include La, Ce, and Nd as major elements and often contain subordinate amounts of other REEs including praseodymium (Pr), samarium (Sm), europium (Eu) and dysprosium (Dy). The lanthanite crystal structure consists of layers of tenfold-coordinated REE-oxygen (O) polyhedra and carbonate () groups connected by hydrogen bonds to interlayer water molecules, forming a highly hydrated structure.