Three-quarter view of a metallographic section of the Mehrgarh amulet
Three-quarter view of a metallographic section of the Mehrgarh amulet. The amulet encased in a resin block was analysed by the UV/visible (180 to 1,000 nm) synchrotron photoluminescence microscope within the Disco beamline, at the SOLEIL synchrotron light source centre. A beamline serves to extract photons, select their energy range and focus the synchrotron beam on the subject. The analysis of this Chalcolithic copper amulet discovered at Mehrgarh in present-day Pakistan confirmed how it was made. This amulet is the oldest known object made by the lost wax process, which uses a model sculpted in a material like beeswax that is subsequently encased in a clay mould. Because wax melts at low temperature it runs out easily when the clay is heated. Molten metal is then poured into the clay mould, filling the empty space left by the lost wax.