Fused Silica Crucibles Made of clay fused silica for melting temperatures up to 2800°F (1538°C). Excellent for melting gold and silver. Available in a variety f sizes or as a set of four. 22-780 has 16 dwt/ 25g capacity. 22-781 has 19 dwt/ 30g capacity. 22-782 has 25 dwt/ 39g capacity. 22-783 has 35 dwt/ 54g capacity.