| Answer | Crossword Clue |
|---|---|
| tantalites | TANTALITE, a black mineral, the main ore from which tantalum is derived |
| tantalite | a black mineral, the main ore from which tantalum is derived |
| ilmenites | A black mineral consisting of iron titanium oxide, of which it is the main ore |
| ilmenite | A black mineral consisting of iron titanium oxide, of which it is the main ore |
| columbites | A black mineral, typically occurring as dense, tabular crystals, consisting of an oxide of iron, manganese, niobium, and tantalum. It is the chief ore of niobium |
| columbite | A black mineral, typically occurring as dense, tabular crystals, consisting of an oxide of iron, manganese, niobium, and tantalum. It is the chief ore of niobium |
