Crucible is a heatproof ceramic or metal container which is used for melting or heating solids for metal, glass and pigment production. Crucibles made of clay were even used in Iron Age like that of Bronze Age. It was used for production of Bronze. During Roman period, crucibles were used to produce alloys. Crucible is appointed bottom vessel with a conical shape and is heated from below. Modern crucibles are made of refractory materials which can withstand high temperature.