The crystal structures of two manganoan 1M-phlogopites and kinoshitalite-1M (Ba, Mn brittle mica) have been re-examined to determine if cation ordering patterns in subgroup symmetries exist. In all cases, the X-ray single crystal data are better explained by the ideal symmetry of C2⁄m, which requires only one tetrahedral site (and no tetrahedral Si–Al order) and only two independent octahedral sites. Since tetrahedral Si–Al order is known for all other brittle micas with Si to Al ratios near 1:1, the kinoshitalite sample of this study, which is from a contact metamorphosed manganese deposit, may have formed under conditions that fail to promote tetrahedral order. However, undetected twinning of the kinoshitalite crystal, which could affect these results, cannot be ruled out.

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Kankite from the Suzukura mine, Yamanashi Prefecture, is found in a wet depression on the dump without accompanying any other secondary minerals than amorphous iron hydroxide. The wet chemical analysis containing 2.25% SO₃ yields two alternative ideal formulae, FeAsO₄·3H₂O and Fe₈ [(As,S)O₄]₇(H₂O,OH)_22–24, the former being close to the original one. Slight differences are found in DTA and TG curves and infrared absorption spectra from those of the original one, but the coincidence of X-ray powder diffraction pattern warrants the substantial identity.

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Phase equilibrium in the central portion of the Cu–Fe–Zn–S system was studied by the evacuated silica glass tube method, and phase relations involving chalcopyrite, intermediate solid solution(iss), bornite, pyrrhotite and sphalerite have been determined between 800° and 500°C. Besides, compositional fields of each solid solution have been clarified. Chalcopyrite appearing only in experiments at 500°C has very limited solid solution field close to the stoichiometric CuFeS₂, and dissolves small amounts of zinc less than 0.9 atm.%. However, iss having an extensive solid solution field dissolves considerable amounts of zinc from 12.7 atm.% at 800°C to 3.3 atm.% at 500°C, and these maximum solubilities of zinc are observed in more iron-rich iss than the cubanite composition at each temperature. Meanwhile, sphalerite solid solution also dissolves considerable amount of copper, and the CuS content in sphalerite increases with that of FeS in sphalerite above 600°C. The maximum observed CuS contents are 10.7 mole % at 800°C, 8.6 mole % at 700°C and 4.6 mole % at 600°C in sphalerite containing higher FeS than 40 mole %. Therefore, entry of copper into sphalerite is dependent upon both temperature and sulfur fugacity.

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The synthesis of a high pressure phase of KAlSi₃O₈ with the hollandite structure was carried out at pressures higher than 14 GPa. The unit cell parameters are: a=9.3244(4) Å, c=2.7227(3) Å and V=236.73(3) ų with the space group I4⁄m. Calculated density is 3.905(1) g/cm³.
The refinement of crystal structure was performed by the ordinary powder X-ray method. Double chains of edge shared MO₆ octahedra run parallel to the c-axis. They share corners to built up dense array which forms square “tunnels”. Potassium atoms are situated in the tunnels and are in the eightfold coordination.
The comparison with the calcium ferrite structure was made.

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