Reference:
▪ Rønsbo, J.G., Balić-Žunić, T., Petersen, O.V. (20167): Dyrnaesite-(La) a new hyperagpaitic mineral from the Ilímaussaq alkaline complex, South Greenland.Mineralogical Magazine, 81, 103–111.
Abstract:
South Greenland. The holotype material descends from an arfvedsonite lujavrite sheet as an accessory mineral. Dyrnaesite-(La) is pale yellowish green, with no cleavage and an irregular fracture. Density is 3.68(2)/3.682 g/cm3 (measured/calculated). It is biaxial, negative, 2Valpha = 47(1)/48 (measured/calculated); alpha = 1.6226(5), beta = 1.6852(10), γ = 1.6982(2); X = c, Y =a, Z = b. The average values of microprobe analyses are (wt.%) P2O5 37.17, SiO2 2O3 16.44, CeO2 20.23, Pr2O3 1.40, Nd2O3 3.47, Sm2O3 0.24, Dy2O3 0.06, Y2O3 0.06. The crystal structure was solved from single-crystal X-ray diffraction data. Dyrnaesite-(La) is orthorhombic, Pnma; a = 18.4662(7) Å, b = 16.0106(5) Å, c =7.0274(2) Å, V = 2077.7(2) Å 3, Z = 4. The structural formula calculated from the diffraction data and microprobe analysis is Na7.89(Ce0.94Ca0.06)1.00(Ca0.12La1.14Ce0.40Pr0.10Nd0.24)2.00(PO4)6, the simplified formula is Na8Ce4+REE2(PO4)6. The crystal structure is closely related to that of vitusite-(Ce), but is distinct from it in several aspects. The five strongest lines of the X-ray powder diffraction pattern are (d Å, (I %), (hkl)); 6.57 (100) (101), 4.62 (40) (301, 230, 400), 3.50 (40) (331), 2.80 (86) (232, 402), 2.67 (54)(060,630).
▪ Rønsbo, J.G., Balić-Žunić, T., Petersen, O.V. (20167): Dyrnaesite-(La) a new hyperagpaitic mineral from the Ilímaussaq alkaline complex, South Greenland.Mineralogical Magazine, 81, 103–111.
Abstract:
South Greenland. The holotype material descends from an arfvedsonite lujavrite sheet as an accessory mineral. Dyrnaesite-(La) is pale yellowish green, with no cleavage and an irregular fracture. Density is 3.68(2)/3.682 g/cm3 (measured/calculated). It is biaxial, negative, 2Valpha = 47(1)/48 (measured/calculated); alpha = 1.6226(5), beta = 1.6852(10), γ = 1.6982(2); X = c, Y =a, Z = b. The average values of microprobe analyses are (wt.%) P2O5 37.17, SiO2 2O3 16.44, CeO2 20.23, Pr2O3 1.40, Nd2O3 3.47, Sm2O3 0.24, Dy2O3 0.06, Y2O3 0.06. The crystal structure was solved from single-crystal X-ray diffraction data. Dyrnaesite-(La) is orthorhombic, Pnma; a = 18.4662(7) Å, b = 16.0106(5) Å, c =7.0274(2) Å, V = 2077.7(2) Å 3, Z = 4. The structural formula calculated from the diffraction data and microprobe analysis is Na7.89(Ce0.94Ca0.06)1.00(Ca0.12La1.14Ce0.40Pr0.10Nd0.24)2.00(PO4)6, the simplified formula is Na8Ce4+REE2(PO4)6. The crystal structure is closely related to that of vitusite-(Ce), but is distinct from it in several aspects. The five strongest lines of the X-ray powder diffraction pattern are (d Å, (I %), (hkl)); 6.57 (100) (101), 4.62 (40) (301, 230, 400), 3.50 (40) (331), 2.80 (86) (232, 402), 2.67 (54)(060,630).