Mineral stream (3)
I believe the answer is:
jet
I believe this is a double definition.
'mineral' is the first definition.
(jet is a kind of mineral)
'stream' is the second definition.
(thesaurus)
(Other definitions for jet that I've seen before include "Very black or fast plane" , "Black gemstone" , "Black aircraft?" , "A spring in ballet" , "Aircraft engine" .)