1mass noun A brown mineral consisting of ferrous carbonate, occurring as the main component of some kinds of ironstone or as rhombohedral crystals in mineral veins.
- ‘Of particular interest are superb specimens of lustrous, pale lavender fluorite crystals, many of which are associated with sphalerite and siderite from what remained of the flats surrounding the Diana vein.’
- ‘The color of the siderite is grayish-white when cleaned, but in most instances it is a dull to iridescent reddish-brown because of alteration to iron oxides on the crystal surfaces.’
- ‘It was the largest orebody found in the Rocky Point zone of the Sawatch Quartzite; ores were of the zinc manto type with marmatite, argentiferous galena, pyrite, and siderite.’
- ‘Overgrowths of fine-grained, bronze-colored siderite are often present on selected faces of the fluorite crystals.’
- ‘The fine-grained sediment of the matrix is composed chiefly of siderite, with lesser amounts of illite, calcite, quartz, and bitumen.’
2A meteorite consisting mainly of nickel and iron.
- ‘On a hillside, three miles above the mouth of the Tualitin, fell, apparently centuries ago, the Willamette siderite, the third largest iron meteorite in the world.’
- ‘The date of formation is estimated to be about 5,000 years ago (Holocene), as a result of the impact of large elements of a siderite (iron meteorite), probably coming from the Perseids, which impact Earth during early August of each year.’
Late 16th century (denoting lodestone): from Greek sidēros ‘iron’ + -ite.
We take a look at several popular, though confusing, punctuation marks.