Minerals and Metals in Ancient India v1.c11.s10.7

v1.c11.s10.7

A noteworthy variety belonging to this group is represented by a number of fine earthenware bangles, usually black in colour, sometimes mottled white, but all distinguished by their fine vitreous texture. The chemical analysis shows a composition of large proportions of lime and magnesia. Their black colour is due to ferrous oxide which indicates that the firing took place in a reducing atmosphere. On the other hand, under the oxidizing conditions prevailing in the kiln, the lime and magnesia would bleach the colour due to iron and the product would emerge white instead. The different colours of the bangles can thus be identified. (MS-II, 686)