Graphites in graphite schist of the Sanbagawa metamorphic belt, Tatarazawa, Fujioka, Gunma Prefecture. Japan, have been identified as ammonia-bearing graphite intercalation compounds (GIC). The ingestion of ammonia and sodium in GIC was confirmed by Nessler's reagent, micro XRD (X-ray diffraction), EPMA (electron probe micro analysis) and micro Raman spectrometer. The EPMA examination clarified that ammonia and sodium were inhomogeneously distributed in graphite grains. The Raman spectra revealed the natural GIC to be consistent with an ammonia-containing graphite. Occurrence of the specimens implied that genesis of natural GIC would have undergone ammonia-bearing hydrothermal process in the past. A finding of graphite intercalation compounds proved that ammonia could be contained by graphite in Sanbagawa metamorphic belt. Likewise, a detection of sodium from graphite has an implication for the existence various graphite intercalation compounds awaiting discovery in such metamorphic rocks.
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