carbonado

n. type of large black diamond usually found in South America

Carbonado, commonly known as the 'Black Diamond,' is a natural polycrystalline diamond found in alluvial deposits in the Central African Republic and Brazil. Its natural color is black or dark gray, and it is more porous than other diamonds.
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Noun
1. an inferior dark diamond used in industry for drilling and polishing
(synonym) black diamond
(hypernym) diamond, adamant
2. a piece of meat (or fish) that has been scored and broiled
(hypernym) meat

n. carbonado, type of large black diamond usually found in South America

(v. t.)
Alt. of Carbonade
  

(n.)
Flesh, fowl, etc., cut across, seasoned, and broiled on coals; a chop.
  

(n.)
A black variety of diamond, found in Brazil, and used for diamond drills. It occurs in irregular or rounded fragments, rarely distinctly crystallized, with a texture varying from compact to porous.