The mineralogical composition of the surface soil horizon (0-15 cm) of Wahiawa soil (Tropeptic Eutrustox) was investigated by X-ray diffraction (XRD), high gradient magnetic separation (HGMS), transmission electron microscopy (TEM), and infrared methods. The concentration of lithiophorite decreased with particle size and none was present in the clay fraction as indicated by XRD. Lithiophorite was further concentrated from the crushed sand-sized fraction by HGMS. Hexagonal, electron-dense, often twinned lithiophorite particles were identified by electron diffraction. Differential infrared (DIR) spectra obtained by dissolving Mn oxides in acidified hydroxylamine hydrochloride (HAHC) indicated lithiophorite as the HAHC-soluble Mn-phase. Lithiophorite compositiion, as revealed by chemical analysis of the HAHC extracts, consisted of appreciable amounts of Mn, Al, Zn, Co and Mg, and less than stoichiometric amounts of Li. Sodium hydroxide treatment apparently altered the lithiophorite, as revealed by the DIR spectrum of the hydroxylamine-soluble fraction of the NaOH-treated sample compared with the untreated sample. The high crystallinity of the lithiophorite was suggested by its resistance to chemical dissolution and narrow X-ray diffraction lines. No evidence for the presence of todorokite or birnessite was found, contrary to earlier reports. Examination of sand-sized nodules by scanning electron microscopy indicated large (2-5 �m) platy lithiophorite crystals at the surface of these nodules. Electron microprobe analysis of these platy particles indicated iron enrichment near the surface. The freshly fractured nodule surface revealed numerous unaltered platy crystals of lithiophorite filling the veins of the nodule.

Studies in the system A12034Si02 under hydrothermal conditions where three different starting materials (amorphous alumina-quartz, amorphous silica-kaolinite, quartz-kaolinite) were investigated in "pinched-tube" experiments1 were followed by a redetermination in sealed-tube experiments of the synthesis fields obtained from amorphous silica-kaolinite and quartz-kaolinite.2 A synthesis diagram for the starting material amorphous alumina-quartz has now been redetermined in sealed-tube experiments. ExperimentalThe pressure equipment used is similar to that already described.2 Modifications to the equipment, in the form of stellite test-tube bombs each coupled to a Bourdon pressure gauge and controlled with an Ether transitrol temperature regulator, enabled more effective control to be attained in some of the experiments. Errors in temperature control were within &l% a t all temperatures.Quartz and amorphous (chromatographic) alumina were mixed in the molecular proportions A1203,4SiOz and Aln03,6SiOz. Samples together with water were placed in silver capsules and sealed. Runs commenced with rapid heating periods (e.g. from room temperature to 400' in 20 min) and were terminated with air quenching. Products were examined with a Philips X-ray diffractometer using filtered Cu radiation.