The effects of crystal orientation and dislocation density on the dissolution rates of feldspar (labradorite, Or₂Ab₄₄An₅₄) were investigated, where three crystallographically different orientations were considered. The single crystal was prepared so as to have one predominant crystallographic face and then it was hydrothermally treated in acid solution at 90°C, 120°C and 150°C. The dissolution from (100) was the fastest of three orientations, and the rates of dissolution from (010) and (001) were almost the same. According to the SEM observations, small etch pits on (100) were arranged along two directions, and those on (010) and (001) were arranged along the cleavage. The dissolution on the plane normal to cleavage is faster than that on the plane parallel to it. Therefore, the microtextures such as cleavage and twinning play a more important role than the structural characteristics in the dissolution of labradorite.

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Baddeleyite, calzirtite, zircon and zirconian garnet were found in skarns at Fuka, Okayama Prefecture, Japan. They occur in association with grandite garnet, vesuvianite, diopside, wollastonite and perovskite. The chemical compositions of baddeleyite, calzirtite and zircon are nearly ideal except for small amounts of HfO₂. Zirconian garnets are rich in titanium and contain up to 7.3wt. percent of ZrO₂. These minerals occur in the contaminated rocks which formed from monzonite magma through hybridization during the formation of skarns.

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Johnbaumite was found as a vein-forming mineral in crystalline limestone near gehlenite-spurrite skarns at Fuka, Okayama Prefecture. It is associated with arsenopyrite, löllingite, garnet, magnetite and calcite. Wet chemical analyses and EPMA of the mineral yield an empirical formula (Ca_4.961Fe_0.005) _Σ4.97(A_s2.991P_0.024) _Σ3.02 O₁₂(OH_0.651F_0.278Cl_0.071) _Σ1.00 on the basis of (O, OH, F, Cl) = 13. The DTA and TG curves, and IR spectrum are measured, and the optical and X-ray diffraction properties agree with previous data.
Johnbaumite from Fuka may be formed by reaction of As, Fe, S, etc.- bearing fluids with limestone.

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