wolframite
/ˈwʊlfrəˌmaɪt/
noun
- A dark, heavy mineral that is the main source of the metal wolfram (tungsten).
- Collectors prize wolframite for its shiny, black crystals.
- Wolframite is often found in quartz veins in mountainous areas.
- The miners extracted wolframite from the ground and shipped it to the refinery.