Preliminary report on mineralogy and geochemistry of opals from the Shikaribetsu area, central Hokkaido

Abstract

Opal boulders taken from the Shikaribetsu area, central Hokkaido, were preliminarily studied on their occurrences, properties and chemical compositions. They suggested hydrothermal activities in the past. Opals showed fluorescence of red, green, orange, yellow and blue colors. Some of them were enriched in gold, silver, mercury, arsenic, antimony and tellurium compared with the crustal abundance of elements.