Mineralogical and Thermal Analyses of a Bangle Shard from Harrappa, an   Indus Valley Settlement in Pakistan
  In this research study we present initial results of a recent project in which mineralogical and thermal analysis were carried out on a terracotta bangle shard from Harrappa. We were surprised to find bentonite clay as the major constituent of the bangle shard. Also we have used knowledge of the mineralogical structure determined through X-ray diffraction and results of thermal analysis to predict value of firing temperature of the bangle shard. 
Saheeb Ahmed Kayani, Rehan ul Haq Siddiqui
physics.gen-ph