Phosphate minerals of triphylite, ferrisicklerite and purpurite were investigated using Mössbauer spectroscopy. The crystal structures of these three minerals are alike to that of olivine except no atoms in the M1 site of purpurite structure. Mössbauer spectra of these minerals at 298K are composed of the multiple doublets with nearly equal isomer shifts but slightly different quadrupole splittings. These multiple doublets are assigned to Fe²⁺ or Fe³⁺ in the M2 sites, showing that the next nearest neighbor(NNN) effect exists in the Mossbauer spectra of these minerals.

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Sibirskite was found in a vein consisting of borate minerals which developed along the boundary between crystalline limestone and skarns at Fuka, Okayama Prefecture, Japan. Sibirskite occurs as aggregates of prismatic crystals up to 0.1 mm long and 0.02mm wide, in association with takedaite, frolovite and calcite. Wet and microprobe analyses of sibirskite from Fuka give the empirical formula Ca_1.004H_1.071B_0.974O₃ on the basis of 0=3. The formula, optical properties and X-ray powder data are consistent with those from the type locality. The space group and cell dimensions determined are P2₁/a, a=8.643(6), b=9.523(2), c=3.567(3) Å, β=119.23(3)° and Z=4. The calculated density is 2.59 g cm⁻³, and agrees with the measured value of 2.58 g cm⁻³.
It is likely that sibirskite at Fuka was formed by late-hydrothermal alteration of takedaite.

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Borcarite was found in a vein cavity which developed along the boundary between crystalline limestone and gehlenite-spurrite skarns at Fuka, Okayama Prefecture, Japan. Borcarite occurs as scattered prismatic intergrowths and euhedral crystals up to 5 mm long and 3 mm wide on the cavity wall, in association with olshanskyite, bultfonteinite and calcite. Wet chemical analyses and EPMA of the mineral yield an empirical formula Ca_3.944(Mg_0.815 Fe_0.089)_Σ0.904B_3.981O_5.705(OH)_6.097(CO₃)_2.066 on me basis of O = 18. The DTA and TG curves, IR spectrum and X-ray diffraction properties agree well with previous data.
It is likely that borcarite was formed as a secondary mineral from brucite in a reaction with late-hydrothermal solution.

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Monazite powder, prepared by heating rhabdophane-(La, Ce, Nd or Sm) at 600°C for 2 hours in air, was dry-pressed to disks and bars. The disks and bars of monazite could be sintered to the relative density (100·bulk density/true density) of larger than 99 % at 1200°C in air without cracking. The linear thermal expansion coefficient of the sintered monazite-(R) ceramics at 1000°C was 10.0×10⁻⁶/°C for R=La, 9.9×10⁻⁶/°C for R=Ce, 9.8×10⁻⁶/°C for R=Nd and 9.7×10⁻⁶/°C for R=Sm. The bending strength was 100±29 MPa for R=La, 183±18 MPa for R=Ce, 97±34 MPa for R=Nd and 135±22 MPa for R=Sm. The monazite did not react with SiO₂ or Al₂O₃ even at 1600°C in air, however, the monazite began to react with CaO above 700 °C in air, forming Ca₃(PO₄)₂ and R₂O₃ (or CeO₂). The monazite ceramics were stable in water, however, they were decomposed by acidic or alkaline aqueous solutions at high temperatures.

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