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Annealing studies have been done on iron-bearing natural samples of red ochre and yellow ochre. The amounts of iron, silicon and aluminium in these samples have been determined by chemical analysis. It has been concluded that red ochre contains iron mainly in the form of alpha -Fe2O3 and in alumina-type octahedra, while yellow ochre has iron chiefly in the form of alpha -FeOOH. The temperature of transformation of alpha -FeOOH to alpha -Fe2O3 was found to be about 400 degrees C. Red ochre was found to exhibit superparamagnetism. Infrared and differential thermal analyses were also carried out to supplement the results obtained through the Mossbauer technique.

Natural chromites taken from three Indian localities, Sukinda, Ladakh and Byrapur, have been studied by Mossbauer spectroscopy. Microscopical and chemical analyses have also been made. Of the four samples studied, three showed normal structure while one showed an inverse spinel structure with small particle size, which indicates that it crystallised at a higher temperature with a faster rate of cooling of the magma. This fourth sample had also suffered hydrothermal alterations. The Fe3+/Fe2+ ratio demonstrates a high oxygen fugacity at the time of formation of all the samples. The Mg/Fe2+ and Cr/Fe ratios suggest that the chromite from Sukinda was the earliest to be crystallised and that the samples from Byrapur were the latest.

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Zinc and cadmium anthranilates do not extract into non-polar solvents alone in the pH range 4.5–6.5. But their extraction is synergistically enhanced in presence of N bases, apparently by displacement of coordinated water. The synergistic effect varies with the bases in the order β-picoline > pyridine > quinoline. The values of extraction constants suggest that cadmium forms more stable complexes than zinc.