- 著者
-
砂川 一郎
- 出版者
- Japan Association of Mineralogical Sciences
- 雑誌
- 岩石鉱物鉱床学会誌 (ISSN:00214825)
- 巻号頁・発行日
- vol.75, no.Special2, pp.55-62, 1980-08-30 (Released:2012-08-03)
- 参考文献数
- 19
Although mineral crystals grow in nature under a broad spectrum of conditions, most natural crystallizations are considered to occur in solution phases, including both high temperature and aqueous solutions. When crystals grow from solution phases, the solidliquid interfaces are essentially smooth, where two dimensional layer-by-layer growth are expected. Judging from growth rates versus supersaturation relation, dislcoation controlled growth is expected for the supersaturation region below σ*, and hopper growth due to twodimensional nucleation mechanism for σ*-σ**, hereas unstable dendritic growth above σ**. Various inhomogeneities in crystals as well as surface microtopographs of crystal OfaOces may appear depending on the growth conditions. It was found on the basis of observati ons on these properties of natural crystals that in most natural crystallization, sprial growth and two-dimensional nucleation mechanisms are predominant mechanisms. This is true not only for crystallization in magma and hydrothermal solutions, but also for crystallization in metasomatic environments. For crystal growth mechanism in regional metamorphic environment, the so-called Ostwald ripening is suggested as principal mechanism, where interstitial solutions play an essential role, and thus the growth is similar to that from solution phases.