Monoclinic ZrO₂ crystals were grown in mixed fluxes: PbF₂-KF, PbF₂-B₂O₃ and PbF₂-KF-B₂O₃. Although crystals grown from the PbF₂-KF flux are tabular, those grown from the mixed fluxes containing the B₂O₃ component always occur in a special mode of aggregation of twinned acicular crystals.
The origin of striations is discussed on the basis of convection due to a change in the solute concentration of the B₂O₃ component in the flux melts.

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Orthoclase cryptoperthites containing the albite component approximately at 35-50 percent are not homogenized below the liquidus but they obviously become homogeneous only after being transformed into the high-temperature form which is stable from about 820°C up to nearly the melting point. Our experiments show that the transformation may be reversible. Presumably, all orthoclase cryptoperthites, in spite of their compositions, show the same behavior mentioned above when heated. A suggestion of the possible mechanism of the transformation and a model of the perthitic structure of orthoclase cryptoperthite are given.

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The new mineral, nambulite, is a lithium- and sodium-bearing hydrous manganosilicate discovered at the Funakozawa manganese mine in the Kitakami mountains, northeastern Japan. Coarse prismatic crystals of the mineral occur in the veinlets in the braunite ore. It has vitreous reddish brown color with orange tint; and perfect (001), distinct (100) and (010) cleavages. Mohs' hardness is 6.5. Specific gravity is 3.51±0.01 (meas.) and 3.49 (calc.). Optically it is biaxial positive with refractive indices (Na-light) α=1.707, β=1.710, γ=1.730 (all±0.002); with 2V=30° ±2° and X'∧c=19°.
Chemical analysis gives: SiO₂ 49.23, TiO₂ 0.01, Al₂O₃ 0.37, Fe₂O₃ 0.40, MnO 40.67, MgO 1.32, CaO 0.81, Na₂O 2.49, K₂O 0.04, P₂O₅ 0.02, Li₂O 1.55, H₂O+ 1.63, H₂O- 0.26, CO₂ 0.19, total 98.99%. The result yields the formula Li_1.00(Na_0.98K_0.01) (Mn_6.95Mg_0.40Li_0.27Ca_0.18Al_0.09Fe⁺³_0.06) Si_10.00O_27.79(OH)_2.21, which may be written ideally as LiNaMn₈Si₁₀O₂₈(OH)₂.
It is triclinic and the crystallographic data are as follows: space group, P1 or P ?? ; a=7.621, b=11.761, c=6.731Å (all ±0.003Å); α=92°46', β=95°05', γ=106°52' (all ±3'); V=573.4±0.3ų; Z=1. Principal powder lines (d in Å) with relative intensities and indices are: 7.11 (25) ( ?? 10), 6.70 (25) (001), 3.56 (20) ( ?? 20), 3.54 (35) (12 ?? ), 3.34 (40) (1 ?? 1, 002, ?? 01), 3.17 (65) ( ?? 02, 031), 3.14 (45) (012), 3.09 (55) ( ?? 12), 3.07 (60) (2 ?? 1), 3.01 (30) (11 ?? ), 2, 97 (80) (0 ?? 2), 2.96 (100) (1 ?? 2), 2.92(70) ( ?? 40, 102), 2.71 (35) (112, 220). Infrared spectrum shows strong absorptions at 1040, 935, 890 and 460 cm^-1.
Nambulite may be an alkaline analogue of rhodonite.
The mineral name is for Professor Matsuo Nambu of Tohoku University.

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The phases present within the system Li₂SiO₃-Mn₂SiO₄-SiO₂+H₂O under total P_H2O=2kb at 740°C are Li₂SiO₃, MnSiO₃ (rhodonite), Mn₂SiO₄ (tephroite), LiMn₄Si₅O₁₄OH (Li-hydrorhodonite) and SiO₂ (quartz). Under 3kb at 500°C, these are Li₂SiO₃, Li₂Si₂O₅, MnSiO₃ (pyroxmangite), Mn₂SiO₄ (tephroite), Li Mn₄Si₅O₁₄OH (Li-hydrorhodonite), LiMn₂Si₃O₈(OH) (Li-serandite)? and SiO₂ (quartz). The pressure-temperature stability field of the end member Li Mn₄Si₅O₁₄OH is wide, ranging from 400°C to 800°C under 1.5kb water pressure. A reversible dehydration of synthetic Li-hydrorhodonite with the above composition vs. anhydrous rhodonite+quartz has been established at 850°C under 1.5kb, P_H2O.
A Li-serandite-like phase with the probable composition, LiMn₂Si₃O₈OH, is stable from 300°C to 600°C under 1.5kb water pressure. This compound decomposes to Li-hydrorhodonite+Li₂SiO₃ with rising temperature (6000-800°C), and finally to anhydrous rhodonite+liquid at over 800°C under the same water pressure (1.5kb).
Solid solution series of Li-hydrorhodonite are formed by the replacement of four Mn²⁺ in one unit formula by Mg²⁺, Fe²⁺ or Ca²⁺. These substitutions reach a maximum when Mg=2.5; Fe=2.0 and Ca=0.5. The unit cell dimensions of the synthetic LiMn₄Si₅O₁₄OH are a=7.549 (2), b=11.778 (3), c=6.726 (2), α=93°11′(1′), β=95°20′(1′), γ=106°19′(1′) and V=569.4 (1) with triclinic space group P^-1. Indexed powder diffraction data are also given for LiMn₄ Si₅O₁₄OH.
The idealized composition of the new mineral nambulite, LiNaMn₈Si₁₀O₂₈(OH)₂ failed to crystallize as a single phase under the diverse conditions here studied.

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The martensitic phase transformations of ZrO₂ and (Zr, Ce) O₂ are characterized by the conspicuous heterogeneous nucleation. The transformation temperatures of the solid solutions with the same lattice parameters change with different heat treatments. The behavior of he transformation changes with grain size and with the repetition of transformation cycle. These changes are due to the autocatalytic nucleation effect and to the new nucleation sites introduced during the cycle of transformation.

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Argentian tetrahedrites have been found, as crystals attaining 15mm across, in siderite-quartz-sulfide veins of the Taishu-Shigekuma mine, Tsushima Island. Electron probe microanalyses revealed that the chemical formula of the mineral is close to (Cu, Ag)₁₀(Fe, Zn)₂Sb₄S₁₃ with extremely wide range of silver content from 3.5 to 23.8 weight percent. The correlation between the unit cell edge (a₀, Å) and the Ag content ([Ag] atomic %) of argentian tetrahedrites has been determined as a₀=10.39₃+0.0128 [Ag].

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Mössbauer spectra have been measured at room temperature on synthetic samples along the join CaMgSi₂O₆-CaFeSi₂0₆ and the join Ca_0.8Mg_1.2Si₂O₆-Ca_O.8Fe_1.2Si₂0₆, as well as on natural samples including ferrosalites, augites, and subcalcic augite. Only those samples of which compositions lie upon the Di-Hd join gave simple spectra. Substitution of the types Ca-(Mg, Fe²⁺) and (Mg, Fe²⁺)-(Fe³⁺, Al) makes the spectrum complex, so that the observed curve cannot be analyzed in terms of two doublets for Fe²⁺, even when we cannot expect more than two sets of nonequivalent positions for Fe²⁺ from X-ray crystallographic data.

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Kilchoanite was synthesized hydrothermally by a new method from quartz-lime mixtures at lower temperatures. The method for hydrothermal treatment is different from that in common use and was employed in purpose to prevent the formation of intermediate phase. The starting mixtures were first heated to the desired temperature without added water and then carried out under hydrothermal conditions with a water compressor. In the case of the common method, the intermediate phase formed in heating process prevent the nucleation of kilchoanite at lower temperatures.

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