from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A black, red-brown, or colorless mineral, essentially (Fe, Mn)(Nb, Ta)2O6, the principal ore of niobium.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A black mineral that is a mixed iron and manganese niobate and tantalate, and is the main ore of niobium and tantalum.
from the GNU version of the Collaborative International Dictionary of English
- n. A mineral of a black color, submetallic luster, and high specific specific gravity. It is a niobate (or columbate) of iron and manganese, containing tantalate of iron; -- first found in New England.
from The Century Dictionary and Cyclopedia
- n. The native niobate (columbate) of iron, a mineral of black color and high specific gravity, crystallizing in the orthorhombic system.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a black mineral that is an ore of niobium and tantalum
There's a crucial element in the manufacture of cell phones, laptops and the like called columbite-tantalite (or coltan).
Tantalum is recovered from ore minerals such as columbite and tantalite.
On Boing Boing Gadgets, this wrenching video in which Eve Ensler explains that Congolese militias use rape to enforce discipline among a slave workforce that mines columbite-tantalite ore, a common raw material for many devices.
Among these riches is coltan - columbite tantalite - a mineral highly prized for its use in a number of consumer electronic products, among other things.
Dogo Nahawa sits amid rolling hills, surrounded by former tin and columbite mines.
Overall, Congo has over half the world's cobalt, one-third of its diamonds, and three-fourths of its vital columbite-tantalite or "coltan," essential for computer chips, circuit boards, mobile phones, laptops, and other electronic devices.
Africa provides columbite-tantalite, the mineral from which most computer chips are made.
Solid minerals like coal, tin and columbite were mined in economic quantities and Nigeria was known to be a major world player in the production of these minerals.
There are deposits of gold, cassiterite (a tin ore) and coltan (columbite-tantalite) ore of a high grade which in 2000 fetched very high prices as a metal used in computer and mobile phone microchips.
Rhenium does not form minerals of its own, but it does occur as a trace element in columbite, tantalite and molybdenite.