black gold

== English == === Etymology === (crude oil; coal; black pepper): From its black colour and high value. === Pronunciation === === Noun === black gold (uncountable) (informal, idiomatic) Raw petroleum; crude oil. Black pepper, in the context of being a historically valuable spice. Black-coloured gold, variously produced by patination, deposition, oxidation, etc. and used in jewellery or in high-technology applications. Coal. ==== Synonyms ==== See also Thesaurus:petroleum. ==== Translations ====