Abstract
An oyelite-bearing vein was found in the gehlenite-spurrite skarn at Fuka, Okayama Prefecture, Japan. Oyelite, previously called 10Å tobermorite, was revealed to be a new mineral of approximate composition 1.0CaO•0.1B2O3•0.8SiO2•1.25H2O. In addition to oyelite, the vein contains bultfonteinite, scawtite, xonotlite and calcite. Among them, oyelite and scawtite are primarily precipitated from fluid and form alternative layers filling the vein fissure. Bultfonteinite and xonotlite are secondarily formed by alteration of scawtite. The thickness of the vein is about 2cm and the thickness of each layer ranges from 1 to 5mm.
