R2: Crystal structure, crystal chemistry, physical properties of minerals, crystal growth and applied mineralogy

[R2-01] Stöber colloid as an analogue of precious opal

[Presentation award entry]

*Tetsuyoshi Takeda¹, Hiroki Okudera² (1. Kanazawa Univ. Nat. Sys., 2. Kanazawa Univ. Geosci. Civil Eng.)

Keywords:precious opal, Stöber process

The formation process of a Stöber colloid was examined as an analog of individual sphere in a sedimentary precious opal. The growth process of particles was divided into three stages: (1) formation of primary particles and their aggregation, (2) adhesion of later-formed primary particles on already formed particles, and (3) no further growth. The above process will occur with quick cooling of a high pH and silica-saturated underground water.