Strontiojoaquinite and bario-orthojoaquinite; two new members of the joaquinite group

These two new minerals permit the joaquinite group to be based on symmetry and occupancy of the REE position. Microprobe analyses gave for strontiojoaquinite: (Na2.28Li0.11Fe1.44box 0.17)box 2Ba4Ti4(O1.27(OH)2.73)-Sr4.01REE0.01(Si4O12)4.1.62H2O. It is monoclinic (P2, Pm or P2/m); a 10.516, b 9.764, c 11.87 A, beta 109°17'; Z = 1. The strongest XRD lines are: 2.801(100), 2.967(72), 3.00(48), 2.923(45), 2.611(42), 2.432(40), 4.30(35) A. H. 51/2, cleavage (001), good, Dcalc. 3.68 g/cm3, biaxial (+) 2V = 35° to 45° with r > v; alpha 1.710, beta 1.718, gamma 1.780, alpha (colourless): a = 19°, beta (colourless) = b, gamma (yellow) = c, alpha = beta < gamma . Bari-orthojoaquinite has the formula (Na0.10Fe3.61Mn0.24)box 2Ba4(Ti3.88Al0.12)(Ba2.88Sr0.88Ca0.08-Al0.019)O4(Si4O12).2H2O. It is orthorhombic (Ccmm, Cc2m or Ccm21); a 10.477, b 9.599, c 22.59 A, Z = 2. XRD lines are: 2.997(100), 2.953(95), 2.824(90), 5.64(70), 2.935(70), 4.30(62), 3.203(50) and 2.602(50) A. The v; alpha 1.735, beta 1.737, gamma 1.80, alpha (pale yellow) = a, beta (pale yellow) = b, gamma (yellow) = c, absorption alpha < beta