Crude Form of Metal Made Into Blocks
Puzzle 20 of Endangered Species Pack
Question is: Crude Form of Metal Made Into Blocks
and the answer is: PIGIRON
Word Meaning:
PIG IRON — (metallurgy, uncountable) A brittle, impure form of iron produced by smelting iron ore which is often shaped into blocks; it is unsuitable for working but suitable for casting, and so is commonly used as an industrial raw material; (countable) a sample of such iron.
Definitions from Wiktionary.