METAL
The ancients used gold, silver, copper, bronze, tin, lead (Num. 31:22; see these different terms). Gold, silver and copper could be separated by mechanical means from the gangues in which they were embedded.
Bronze began to be obtained by fusing copper with cassiterite, which is a tin oxide found in deposits. Iron already requires a much more elaborate production process.
It was already known in ancient times (see IRON), but the secret of its obtaining and manipulation was jealously guarded (cf. Gen. 4:22; Deut. 3:11; Jb. 19:24; 28:2; 39:23 ; 40:18; 41:27; regarding the Philistines’ monopoly of iron technology, cf. 1 Sam. 13:20, 21). Smelting furnaces have been found in tell el-Hesi and tell Yemme