Morimotoite, Ca3TiFe2+Si3012, has been found in contaminated rocks which are considered to be a kind of endoskarn at Fuka, Bitchu-Cho, Okayama Prefecture, Japan. Morimotoite is derived from andradite, Ca3Fe3 § by the substitution Ti + Fe z+ = 2Fe 3 § It is associated with calcite, vesuvianite, grossular, wollastonite, hematite, prehnite, fluorapatite, perovskite, zircon, baddeleyite and calzirtite. It is cubic with space group Ia3d. The unit cell dimension a is 12.162(3) A. Its refractive index n is 1.995(2) and the density 3.75(2) g cm -3 (meas.), 3.80 g cm -3 (calc.). The Mohs' hardness is 7.5. Calculation of the analytical data on the basis of twelve oxygen atoms and eight cations shows that this mineral has a simplified chemical formula Ca3 (Ti,FeZ §247247 where Ti > Fe 2+ > 0.5. Morimotoite was synthesized at low oxygen fugacities, 650 and 700~ and 1 kbar total pressure.

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Nifontovite and olshanskyite, two rare hydrous calcium borate minerals, have been found in crystalline limestone near gehlenite-spurrite skarns at Fuka, Okayama Prefecture. Nifontovite occurs as aggregates of tabular crystals up to 5 cm long and 1.5 cm wide, and rarely as enhedral crystals up to 1 mm long. Olshanskyite occurs as anhedral masses, or as micro-twinned platy crystals up to 1 cm long. Wet chemical analyses give the empirical formulae Caa.052Bs.991Ot.03s(OH)Iz'l.96H20 and Ca2.sssB3.997(OH)ls on the basis of O = 20 for nifontovite and OH=18 for olshanskyite, respectively. The formulae are consistent with those from type localities.The X-ray powder data for these minerals were determined with accuracy. The unit cell parameters of nifontovite agree closely with those published previously. X-ray studies show that olshanslodite is triclinic with the possible space group P! or P1 and a = 9.991(5), b = 14.740(11), c = 7.975(3) A, 0c = 94.53(4), [3 = 69.08(3), y = 112.44(5) and Z = 3. The density 2.19 g cm -~ (meas.) obtained for olshanskyite agrees with the estimated ideal value 2.31 gcm -3 (calc.). Nifontovite was formed by hydrothermal alteration of an anhydrous borate, and olshanskyite was formed by hydrothermal alteration of nifontovite and the anhydrous borate.

Clinotobermorite, CasSi6(O,OH)Is'5H20, has been found as a vein-forming mineral in gehlenitespurrite skarns at Fuka, Okayama Prefecture. It is associated with tobermorite, plombierite, apophyllite, and calcite. The clinotobermorite is colourless or white and occurs as tabular or acicular crystals. It is monoclinic with the space group Cc or C2/c. The unit cell dimensions are a 11.331, b 7.353, c 22.67 ~, [~ 96.59 ~ Microtwinning and stacking disorder on (001) are observed. On heating the clinotobermorite at 300 ~ the 002 spacing is reduced from 11.3 to 9.3 ~k. Its refractive indices are 1.575, 13 1.580, y 1.585, and the density 2.58 g/cm 3 (meas.), 2.69 g/cm 3 (calc). The Moh's hardness is 4.5. Calculation of the analytical data on the basis of six tetrahedral cations shows that this mineral has a simplified chemical formula Cas.3Si6(O,OH,F)aa-5H20. The chemical composition and the unit cell are closely related to those of tobermorite. It is most likely that clinotobermorite is a low-temperature polymorph of tobermorite.

Kusachiite, CuBi204, has been found in a calcite vein cutting gehlenite-spurrite skarns at Fuka, Okayama Prefecture. It is associated with calcite, henmilite, sillenite, bakerite, tenolite, bultfonteinite, apophyllite, cuspidine and thaumasite. Kusachiite occurs as prismatic crystals or globular aggregates of platy crystals. It is black, opaque with a metallic lustre. Kusachiite is tetragonal with space group P4/ncc, a = 8.511 (2) (17)(200), 2.913 (16)(002), 2.404 (13)(202), 1.728 (12)(213), and 1.652 (9)(332). The Mohs hardness is 4.5, and the density is 8.5(3) g/cm 3 (meas.) and 8.64 g/cm 3 (calc.). Cleavage is perfect on { 110}. Six electron probe analyses gave the following mean values CuO 13.91, Bi203 86.00 and total 99.91 in wt.%. The empirical formula calculated on the basis of O = 4 is Cu0.96oBi2.02704 with the simplified formula CuBi204.