An Encyclopaedia of Indian Archaeology v1.c21.s14.4

v1.c21.s14.4

Physically the objects have a hardness of about 6 and a specific gravity of about 2·75. The chemical composition and specific gravity correspond to those of talc, but the hardness is much higher than that of natural talc. When steatite is heated it loses part of combined water (H₂O⁻) and becomes harder. When heated to about 1100° C. The hardness rises to about 6. It is concluded therefore that these objects were heated to a high temperature in order to harden them and render them more durable and abrasion-resistant. The heat also whitened them considerably and largely removed the green and brown colours although in section the original colours can be seen. Objects have however been found with a hardness of about 2 which is the hardness of unburnt talc. Such objects were evidently not subjected to any heat treatment.