Minerals and Metals in Ancient India v1.c22.s1.5

v1.c22.s1.5

Marshall (1975: chapter 25) referred to a natural stone, which looked like artificial porcelain, found in Taxila. He named it porcelain-agate, a term new to geology. It was found in the form of round flat disks, evidently used for some kind of inlay work during the Maurya period. Analysis of a sample at the Royal College of Science, England, by Prof. H.B. Baker, yielded the values: 98.40 per cent silica, 0.99 per cent ferric oxide and alumina, 0.12 lime and 0.05 magnesia. Baker concluded that porcelain-agate was “a natural substance produced, possibly in a volcanic region, by the long-continued heating of ordinary quartz”. The source of occurrence of this material is not known.