Relict staurolite was newly found, together with metastable kyanite with or without Zn-rich spinel, in the sillimanite+K-feldspar zone grade quartz-rich Takanuki pelitic gneisses at three localities near Takanuki. It occurs as anhedral grains, up to 0.2mm in diameter, completely included in plagioclase single crystals, and is much Zn-richer, containing up to 2 wt. % ZnO, than staurolites in the nearby silica-undersaturated metalateritic rocks. The relict staurolites in the pelitic gneisses do not show any breakdown texture to the garnet+sillimanite+spinel assemblage, which is conspicuous in the metalateritic rocks. This may be due mainly to the high partial pressure of H₂O locally prevailed around relict staurolites within plagioclase single crystals in pelitic gneisses, that resulted from dehydration of a trace amount of staurolite. On the other hand, kyanite associated with Zn-rich spinel may have been formed after staurolite which was located at the grain boundary of host plagioclase crystals, because H₂O released from staurolite could escape along the grain boundary. This, in turn, suggests that some kyanite was formed as a product of staurolite breakdown in the absence of quartz.

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A method is proposed to describe quantitatively various zircon crystal forms projected either on the plane {100} or {110}. When the crystal planes observable from one direction are assumed to be the same size as those on the opposite side, four indexes can be calculated: the flatness index is the ratio of the total thickness to the total width, the elongation index is the ratio of the prism height to the sum of the total height and the total width, the prism index is the ratio of the total width of {100} to the prism perimeter, and the pyramid index is the ratio of the pyramid height to the height of {211}. All these indexes range from 0 to 1 for almost all zircon, and, regardless of the direction of observation, they remain virtually unchanged. This technique will provide useful clues not only to correlate igneous formations but also to estimate the physico-chemical conditions of the host rock of zircon crystals.

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Hydration states of hydromuscovites under conditions of 80% and 50% R. H. and glycerol solvation after saturation with various kinds of cations in the expandable interlayers were examined by means of Fourier transform analysis.
At 80% R. H., Ca-saturated specimens showed one- and two-layer hydration states of expandable layer and the ratios of two-layer to one-layer hydration states decrease with increasing the proportions of mica layer components. At 50% R. H., Ca-saturated specimens indicated a decrease in two-layer hydration and an increase in one-layer hydration as compared with those of the specimens at 80% R. H. Glycerol solvated complexes of Mg-saturated specimens showed that the specimens contain one-layer glycerol complexes with spacing of about 12.5Å.
These hydration states of the hydromuscovites are different from those of smectites and expandable layers of regularly interstratified mica/smectites, and it is considered to be due to their high layer charge in expandable layer.

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The fabrics and presence of celestite in the carbonate cements in the reefal limestone of Gebel El Rusas Formation and the sabkha sequences of the Abu Dabbab Formation (Middle Miocene) suggest deposition in a hypersaline vadose regime. The recorded carbonate cements are represented by paleoflowstone crusts; spheroidal and hemispheroidal structures and giant plaeoaragonite ray-crystals deposited in fenestrae and as crusts within the Miocene sediments.
The carbonate cements occur in the form of polycrystalline calcite pseudospar and fibrous calcite resulting from paramorphic replacement of aragonite in Mg-poor fresh water vadose regime. Traces of native sulfur is formed together with secondary gypsum and calcite in the surficial layer of the Abu Dabbab evaporites. It is formed in a localized microenvironment in the fresh water vadose regime due to bacterial activity on sulfate deposits.

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