Green’s Dictionary of Slang

1. black women in general, as sex objects.

1969

H. Rap Brown Die Nigger Die! 30: ‘You know any nice colored girls?’ So whitey would get him a little taste of black gold for $10 or $15 and Black people helped him.

2. oil.

1962		W.R. Burnett Widow Barony 49: ‘You—Black Boy. Where you go?’ Beetyan asked Willie. ‘For a ride, old dad,’ said Willie. ‘We like maybe to get the stink of black gold off us’.
1975		L. Dills CB Slanguage.

3. (drugs) high potency marijuana [black n. (1i) + Acapulco (gold) n.].

1982		Abel Marihuana Dict.
2001		ONDCP Street Terms 3: Black gold — High potency marijuana.