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Single crystals of andradite, having the morphology of tetragon-trioctahedron, were found in sandstone bed and skarn-pebbles therein of typical Triassic Ladinian formation at Kurobayama, Onoda city, Yamaguchi Prefecture, west Japan. The largest crystal is 1.5 cm across and 3.78 g in weight. An example of chemical analyses for the andradite is given as follows : ( Ca22.65Mg0.11Fe20+0.66Mn0.40) 23.82 (Fe3+15.96Al0.14)16.10 Si24.02O96.00 Lattice parameter. 12.042 A, specific gravity 3. 58, refractive index 1.8830 and magnetic susceptibility 60x 106 emu/g are obtained.The growth, dislocation and deformation history of this garnet was analysed from the surface microtopographic features left on the as-grown surface.The finding of this garnet suggests the existence of skarn-type ore deposit and its related acidic plutonism during the periods between late Permian and middle Triassic in the western region of Yamaguchi Prefecture.

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Ilmenitefrom East Ongul Island,

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