Host: Japan Association of Mineralogical Sciences
Chalcedony and agate are aggregates of cryptocrystalline crystals, and composed of quartz and moganite. Numerous optical and transmission electron microscopies observations were carried out, and these results have revealed the characteristic features, e.g., development of Brazil twin lamellae, intergrowth with moganite, optically length-fast form. However, textural data from 1µm to 10 nm sized are not enough to clarify the relation between TEM and optical microscopy observations. We carried out to observation the fine textures of chalcedony and agate by using a field emission type scanning electron microscopy. The results suggest that the textures are grouped mainly to three types and that the optical textures are related with the secondary particle composed of aggregate of nanometer-sized crystals.
