Element, transition metal
Specific gravity: 8.57
Colour: Silvery white
Solubility: Insoluble in nitric and hydrochloric acids
Melting point: 2,477oC
Boiling point: 4744oC
17 parts per million by mass, 3.7 parts per million by moles in the Earth's crust
4 parts per billion by mass, 50 part per trillion by moles in the Solar System (ChC).
Niobium is not recognised as a valid mineral species by the IMA, although it has been reported in the native state from a handful of terrestrial localities, and from the moon.
Niobium-bearing minerals include:
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