Oolitic calcite in Shirahone Hotspring as nationally designated special natural monument

Abstract

The oolitic calcite from Shirahone hot spring is famous from the end of 19th century . It was designated to special natural monument in 1952. However, after a study of Sato (1922), the modern mineralogical study was not done. I observed microstructure of the oolitic calcite using SEM-EDS this time. As for the spherical calcite, a concentric-formed transparent part (long prismatic calcite) and an translucent part (granular calcite) make alternated layers.