Glass and glass products

• Published in: Europhysics news Vol. 37; no. 6; pp. 23 - 27
• Main Author: Lehmann, Jean-Claude
• Format: Journal Article
• Language: English
• Published: EDP Sciences 01.11.2006
• ISSN: 0531-7479; 1432-1092
• DOI: 10.1051/epn:2006602

It was apparently by chance that, about 4000 years ago, glass as an artificial material was discovered. Actually natural glass exists in nature and has been used since a very long time. Fulgurites, produced by the impact of a lightning on sand seems never to have been used, but obsidian, of volcanic origin has been used by men to make arrows tips, and by women to make mirrors.. supposed to reflect also the soul! But it was when natron blocks, a sodium carbonate largely used in antiquity to desiccate the body in the process of mummification, were put by accident in contact with sand in the preparation of a meal, that is with a fire, that the fusion point of silica (actually sand) was sufficiently lowered as to obtain the melting of this mixture, and with its further solidification to realise the first man-made glass. One may say that the whole glass industry started from this event. Pure silica, SiO2, exists under two different atomic structures: quartz, a trigonal crystal also found in nature and vitreous silica the structure of which is disordered, that is 'amorphous' or 'glassy'.