三重県水晶谷産大江石

Abstract

Oyelite was found from serpentinite body in Suisho-dani, Ise City, Mie Prefecture, Japan. Oyelite, which occurs as white massive aggregates in rodingitic rock derived from gabbroic pegmatite, is accompanied with hydrogrossular, 11Å-tobermorite, bultfonteinite, ettringite group mineral, apophyllite and calcite. The cell dimensions are a=11.23(1)Å, b=7.24(1)Å, c=20.42(1)Å, and V=1, 660(2)Å3. The empirical formula (based on O=29) by wet chemical analysis is Ca10.01, B1.74 Alp0.19 Sie8.05 O29 12.25 H2O, corresponding to the ideal formula Ca10 B2 Si5 O29 12 H2O. The endothermic peak in DTA appears at 200°C, and the exothermic peak appers at 8011°C. The major weight loss by TG is observed in the regions at about 200°C. Oyelite, which heated at 300°C and 1, 0001°C for 1 hr, changes into 9.3Å-tobermorite and wollastonite in the X-ray diffraction patterns. The infrared absorption spectrum at 25°C gives strong peaks at 3, 500-3, 000, 1, 440, 965, 857, and 463cm-1, and after heating at 300°C, the I. R. spectrum indicates absorption peaks at 3, 600-3, 400, 1, 390, 970, and 475cm-1. Oyelite was produced from a hydrothermal solution with BF3, in the later stage of the rodingitization (calcium metasomatism).