columbite
columbite (niobite, tantalite) A mineral oxide (Fe,Mn)(Ta,Nb)2O6; when Ta > Nb the mineral is called tantalite, but when Ta < Nb it is called columbite; sp. gr. 5.2–6.5, increasing with increasing Ta content; hardness 6.0–6.5; orthorhombic; weakly magnetic; black or brownish-black; very dark red streak; sub-metallic lustre; crystals normally tabular and short prismatic forms, and can also be blade-like; cleavage pinacoidal; occurs in granites and pegmatites in association with high-temperature minerals, e.g. cassiterite, wolframite, tourmaline, quartz, and feldspar. It is a major ore mineral of niobium.
More From encyclopedia.com
Lite , lite •affright, alight, alright, aright, bedight, bight, bite, blight, bright, byte, cite, dight, Dwight, excite, fight, flight, fright, goodnight, h… Bight , bight •affright, alight, alright, aright, bedight, bight, bite, blight, bright, byte, cite, dight, Dwight, excite, fight, flight, fright, goodnight,… Jadeite , jadeite Isolated, rare mineral of the clinopyroxenes with the composition NaAlSi2O6; sp. gr. 3.2–3.4; hardness 6; granular crystals or massive; jade… Snakebite , snakebite •affright, alight, alright, aright, bedight, bight, bite, blight, bright, byte, cite, dight, Dwight, excite, fight, flight, fright, goodnig… Troglodyte , trog·lo·dyte / ˈträgləˌdīt/ • n. (esp. in prehistoric times) a person who lived in a cave. ∎ a hermit. ∎ a person who is regarded as being deliberate… wolframite , wolframite Ore mineral for tungsten, with the formula (Fe,Mn)WO4; sp. gr. 7.0–7.5; hardness 5.0–5.5; monoclinic; grey-black to brownish-black; browni…
About this article
columbite
All Sources -
NEARBY TERMS
columbite