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Humite group minerals occur in the marbles of granulite grade at Ambasamudram, southern India. Detailed mineralogical and mineral chemical characterization indicate the mineral is a flourine-rich titanian-poor variety of clinohumite. Average M Ti /Si values of 2.22 with typical XRD pattern indicate the mineral to be clinohumite. Petrological constraints on the clinohumite formation shows a high temperature (>7008C) and low a CO 2 during its formation. The fluorine content of these clinohumites is the highest reported in any environment, with F/(F+OH) ratio reaching a value of 0.70. The high fluorine content reflect the high P T condition of formation. The OH content of the clinohumites is around 0.59 mole fraction. Preliminary FTIR spectra of the clinohumites show eight sharp absorption peaks between wave numbers 3700 and 3400 cm 1 and a broad absorption band with a peak at 3840 cm 1 . The sharp peaks are due to OH in the clinohumite. The high fluorine content of the Ambasamudram clinohumites possibly resulted from the isochemical reactions involving (OH-F) silicates such as amphiboles or phlogopites. The internal fluid buffering is also supported by the stable isotope as well as the petrological studies of the marble assemblages.

Micro-FTIR (MFTIR) measurements were carried out on the natural recrystallized quartz in Ryoke granites from Mt. Takamiyama. The recrystallized quartz always shows a very strong IR absorption band at 3596 cm 1 (2.10 abs. cm -1 (normalized absorbance) under unpolarized conditions at room temperature). However, naturally deformed quartz does not show this absorption band, but only a characteristic broad band centred at 3400 cm -1. This shows that the predominant forms of H-related species in the recrystallized quartz are different from those in naturally deformed quartz. The 3596 cm -1 band is not affected by room-temperature X-ray irradiation or by annealing at temperatures of up to 600~ and shows broadening and a positive peak shift with temperature in in situ high temperature measurements. Polarized-MFTIR measurement shows that the band has a strong polarization; the OH dipole is oriented at 35 ~ to the a-axis in the (1010) plane and is isotropically distributed in the (0001) plane. From the stability of the band at high temperatures and against irradiation and its sharpness, the band is considered to be due to the AI(H) type point defect with no alkali which might occupy a structural position in the quartz structure.

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