Systematic annealing experiments on fission tracks in different planes of apatite are carried out in order to observe its anisotropic behaviour. The anisotropic effect is found to increase with annealing rate. It is observed that the fission tracks parallel to the c-axis in apatite crystal exhibit a far greater resistance to annealing than those registered in any other orientation. The annealing rate, Va and the activation energy, Ea, are also found to vary with the crystallographic orientation.

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A jadeite rock from Oosa-cho, northern part of Okayama, is associated with serpentinite of the Sangun metamorphic belt. It consists predominantly of jadeite with such accessary minerals as grossular, analcime, prehnite, vesuvianite, natrolite, thomsonite, stronalsite, zircon, deweylite, chlorite and diopside. It is cut by many veinlets composed of one or more of grossular, analcime, vesuvianite, stronalsite, chlorite and zeolite minerals.
On the electron microprobe image, some of jadeite crystals show a growth zoning of diopsidic (Jd₉₆Di₃Fs₁) and pure (approximately Jd₁₀₀) parts. Some crystals of garnet show chemical zoning. The core is poor in TiO₂, FeO and CaO, but rich in Al₂O₃ as compared with the rim. Zircon occurs sporadically. Under the microscope, a few grains of stronalsite are observed. Its chemical composition is very similar to the ideal formula, Na₂SrAl₄Si₄0₁₆. Ba-rich parts are also recognized in a stronalsite crystal.

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The origin of ribbon-like morphology of hematite crystals twinned by rotation around [0001] with composition plane (10-10) was accounted for as due to the accelerated growth at the twin junction by heterogeneous two-dimensional nucleation around the selectively precipitated crystallites of Mn–Ti rich phase, and not due to the simple presence of a re-entrant corner.

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Phase relations in the system gehlenite (Ak₀Ge₁₀₀ or Ak₂₀Ge₈₀)–SiO₂–H₂O were investigated at 1 kbar water pressure and at temperatures from 350° to 750°C. Crystalline phases formed in the gehlenite end-member (Ak₀Ge₁₀₀)–SiO₂–H₂O system are bicchulite, garnet, anorthite and corundum (or boehmite), and those in the gehlenite solid solution (Ak₂₀Ge₈₀)–SiO₂–H₂O system are vesuvianite, xanthophyllite and diopside in addition to the phases formed in the end-member system. The results of the solid solution system are more consistent with the natural alteration reactions than the results of the end-member system.
The coexisting crystalline phases observed in the solid solution system change successively with the fall of temperature as follows: (1) gehlenite + garnet, (2) gehlenite + vesuvianite ± garnet, (3) bicchulite + xanthophyllite + vesuvianite and (4) bicchulite + vesuvianite ± garnet. The assemblage (1) is stable at temperatures above 720°C and that of (2) is stable at temperatures between 610°C and 720°C. The stability boundary between the assemblages (3) and (4) is inclined: 340°C for no silica-addition, 450°C for the added silica/gehlenite = 0.03 and 500°C for the added silica/gehlenite = 0.06. The large amounts of silica-additions result in the assemblage of garnet + anorthite ± diop-side at temperatures between 350°C and 750°C.
Cell dimensions of hydrogrossular, i.e., degrees of hydration, vary depending not only on the formation temperatures but also on silica deficiencies of the starting materials. Cell dimensions of vesuvianite vary in the same manner as grossular. A linear relationship between the cell dimensions of garnet and those of vesuvianite was observed in the present experiment.
Examples consistent with the present experimental results are found in natural mineral assemblages from many localities. The alteration conditions of gehlenites at Crestmore and Kushiro, correspond to the mineral assemblage (2), whereas those at Akagane mine corresponds to the assemblage (3). The alteration conditions which were commonly observed at Fuka correspond to the assemblage (4). The experimental results may be applied to processes and conditions of natural alteration reactions of gehlenite at other localities as well. The same correlation between the cell dimensions of garnet and those of vesuvianite as in the synthetic experiments is seen in natural specimens from Fuka and Kushiro.

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A new mineral stronalsite, SrNa₂Al₄Si₄O₁₆, is the strontium analogue of banalsite and named after the chemical composition. It is orthorhombic, Ibam or Iba2, a=8.415(4), b=9.901(4), c=16.729(9)Å, Z=4. Average of five microprobe analyses is SiO₂ 39.13, Al₂O₃ 32.70, CaO 0.17, SrO 15.72, BaO 2.29, Na₂O 9.99, total 99.91%, corresponding to (Sr_0.94Ba_0.09Ca_0.02)_Σ1.05Na_1.99Al_3.95Si_4.01O₁₆ on the basis of O=16. It is white in colour with a vitreous luster and white streak. H.(Mohs)=6^1⁄2. No cleavage. Density (g/cm³): 2.95(meas.), 2.95(calc.). It is optically biaxial and positive, 2V=32°(meas.), dispersion indiscernible. Refractive indices: α=1.563(2), β=1.564(calc.), γ=1.574(2). Optic orientation: a=Y, b=Z, c=X. Colourless in thin section. Non-fluorescent under short and long wave ultraviolet lights.
It occurs as veinlets cutting meta basic tuff xenolith enclosed in serpentinite quarried at Rendai, Kochi City, Japan, in association with slawsonite and pectolite. The formation was favoured by a silica-poor condition and concentration of strontium coming from a disintegration of basic plagioclase into such a strontium-excluding calc-silicate as grossular-hydrogrossular. A strontium-sodium-aluminum silicate from Mt. Ohsa, Okayama Prefecture (Kobayashi et al., 1984) has been proved to be the second stronalsite, in which strontium is partially replaced by barium and minor calcium.

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Exsolution textures of pyroxene minerals are regarded as effective indicators for the sake of deducing the thermal histories. With the view of elucidating quantitative relations of texture to cooling rate (C.R.) and chemical composition in pyroxenes, the size variations of “spinodally-decomposed (001) lamellae” in synthetic augite were examined with transmission electron microscope (TEM). The textural differences were investigated through cooling rate experiments (cooled over the range 1°C/h to 120°C/h) using homogeneous starting glasses with composition of Wo_32.3En_58.2Fs_9.5 and Wo_31.0En_42.7Fs_26.3. All experiments were performed under the condition of regulated partial oxygen pressures with a programmed cooling temperature system. Chemical compositions of these samples were determined with electron probe micro-analyzer (EPMA) and analytical electron microscope (AEM). Quantitative relations between lamella wavelength (λ) and C.R. are reported, which were found in the two sets of augites well defined in their composition. The present results include the recalculated data from McCallister (1978) and Grove (1982). The relations between λ and C.R. could be described at the value of Wo/(Wo+En+Fs) fixed to 0.3 as follows:

Fs/(Fs+En)=0	:	λ=110+400×(C.R.)−1⁄3
Fs/(Fs+En)=0.14	:	λ=100+350×(C.R.)−1⁄3
Fs/(Fs+En)=0.40	:	λ=70+250×(C.R.)−1⁄3
(λ in Å and C.R. in °C/h)

The relation of wavelength to cooling rate and composition can be discussed quantitatively and the average cooling rate in natural augite could be appraised by applying these equations.

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The crystal structure of goyazite has been re-refined using the counter data, giving R=0.039 for 417 reflections. Formula: SrAl₃ (OH)₆ [PO₃(O_1⁄2(OH)_1⁄2)]₂. Cell dimensions: a=7.015(3), c=16.558(6)Å, space group R-3m, Z=3. Goyazite has a structure analogous with that of alunite and/or crandallite. Either apical O of a pair of P tetra-hedra is replaced by OH. Mean distances of M–(O, OH) are as follows: P–(O, OH) 1.535Å, Al–(O, OH) 1.896Å, Sr–(O, OH) 2.748Å.

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