Minerals and Metals in Ancient India v1.c11.s13.4

v1.c11.s13.4

The body material of this peculiar class of ware is powdered steatite which is bound together with a flux. Originally, the objects of this material is soft and cream-white, but the presence of little copper oxide on it leaves no doubt that these were originally coloured blue or green, like ordinary faience. The faience objects are covered with a distinct layer of glaze which must have been applied separately especially in the second firing. Different colours are found, about which we have mentioned earlier. The blue shades owe their colour to copper oxide while the green contains iron oxide in addition. The black or dark maroon glaze contains an excess of manganese oxide. Another specimen of glass consist of silicates of soda and lime and a metallic oxide for the colour. These were prepared by the fusion of an alkali, sand, saltpetre and chalk with a metallic oxide for the coloured varieties. This simple method was used to produce glaze. (MS-II, 686-88)