A black, gray, or brown mineral which consists mainly of uranium dioxide and is the chief ore of uranium.pitchblende is a variety of uraninite
- ‘It converts uranium dissolved in water to uraninite, which is much less soluble; this ‘reduction’ process creates small charges of electricity.’
- ‘For example, the presence of pyrite and uraninite can be explained if the atmosphere and surface waters 2.7 billion years ago contained little or no oxygen, a possibility that is supported by several lines of evidence.’
- ‘Using this as a standard he acquired a sample of Norwegian uraninite, had this converted to lead tetramethyl, and then measured the abundance of radiogenic lead.’
- ‘A comprehensive discussion of the mineralogy and occurrence of uraninite has been given by Frondel, to which the reader is strongly referred.’
- ‘Other accessory minerals are apatite, zircon, monazite, huttonite and rare xenotime, uraninite and betafite.’
- ‘Unusual specimens consisting of massive silver associated with uraninite and a variety of cobalt and nickel arsenides were available at one time from mines in the Great Bear Lake region, Northwest Territories.’
- ‘The mountain is one of the most important deposits of barite, a barium bearing mineral that exhibits more gravity than any other mineral with no metallic constituent elements with the exception of uraninite.’
- ‘At Azegour, Morocco, uraninite occurs in tactite with molybdenite, chalcopyrite, barite, pyrite, hematite, and garnet.’
- ‘Arsenopyrite, cassiterite, molybdenite, wolframite, uraninite, and several of the common sulfides have all been observed at various locations.’
- ‘Early investigators recognized bitumen (referred to then as carbon) as having a strong spatial relationship with gold, uraninite and pyrite.’
Late 19th century: from urano- + -ite.
We take a look at several popular, though confusing, punctuation marks.