black gold

Definitions

1. Raw petroleum; crude oil.
   idiomatic, informal, uncountable
2. Black pepper, in the context of being a historically valuable spice.
   uncountable
3. Black-coloured gold, variously produced by patination, deposition, oxidation, etc. and used in jewellery or in high-technology applications.
   uncountable
4. Coal.
   uncountable

Equivalents

Examples

“With the black gold already gushing from his country's wells, the Iranian monarch did not show⟳ much interest⟳ in what the Republic of China had to offer⟳ in agricultural know-how, commerce, and cultural interflow.”

“They [the railways] are mostly remnants of a long-gone coal industry, laid out largely to bring⟳ the black gold from the mines to the waterways.”

CEFR level