open access

https://hdl.handle.net/2115/38517

Study of Macroscopic and Microscopic Reaction Textures Associated with Corundum of Balangoda Region, Sri Lanka

英語

Mineralization

2004

Graduate School of Science, Hokkaido University

Neo-Science of Natural History: Integration of Geoscience and Biodiversity Studies : Proceedings of International Symposium on "Dawn of a New Natural History - Integration of Geoscience and Biodiversity Studies" March 5-6, 2004, Sapporo

129-136

International Symposium on "Dawn of a New Natural History - Integration of Geoscience and Biodiversity Studies". 5-6 March 2004. Sapporo, Japan.

Corundum is the most sought after gem variety among Sri Lankan gem minerals. Locations of most of the gem quality stones were identified as alluvial. The in-situ corundums rarely show a gem quality and are mostly associated with macroscopic and microscopic reaction textures. Studies of these textures, associated reactants and the intrusion of corundum by reaction products using electron probe microanalysis and energy dispersive x-ray analysis reveal that hydrous minerals such as phlogopite mica play an important role in promoting such reactions. Because of these reactions corundum is likely to be fractured and the fractures are often filled with reaction products. Hence the gem quality is not retained in most corundum after their formation. Also the natural shielding effect, called plagioclase shielding that protects corundum against the retrograde reactions, is found to be responsible for the production of valuable gem quality stones.

会議発表論文

Version of Record