A crucible being heating on a clay triangle over a Bunsen burner.
A crucible is a container used for chemical reactions at high temperatures, for calcination, or for melting metals. Crucibles are made earthenware, porcelain, quartz, or graphite; or, of metals such as iron, platinum, nickel, or silver. Metal crucibles may be damaged by alloy formation if metals are melted in them. Industrial crucibles are generally large and line with refractory materials.