siderite

IPA: sˈɪdɝaɪt

(uncountable, mineralogy) a widespread brown mineral, FeCO₃, having the structure of calcite
(countable) an iron meteorite
An indigo-blue variety of quartz.
(obsolete) magnetic iron ore; lodestone

Examples of "siderite" in Sentences

This compound occurs in nature as siderite, and is a valuable ore.
English ores also contain considerable iron carbonate or siderite.
Any automaton was sure to register her as a siderite, and ignore her.
Among these are barite or heavy spar (BaSO4), used as a pigment, which is found in the strata of the Kirtland shale; siderite or brown spar
The article also includes the first ever figure of the specimen, showing it in its unprepared, siderite-encased case (a scan of that figure is included here).
“Many people have assumed that the hematite in ancient rocks formed by the oxidation of siderite in the modern atmosphere,” said Hiroshi Ohmoto, professor of geochemistry, Penn State.
“If hematite were formed by the oxidation of siderite at any time, the hematite would be found on the outside of the siderite, but it is found inside,” he reported in a recent issue of Nature Geoscience.
The original condition is indicated by the facts that deep below the surface, in zones protected from weathering solutions, siderite and greenalite are abundant, and that they show complete gradation to hematite in approaching the surface.
Iron likewise combines with a considerable variety of substances other than oxygen; and some of these compounds, as for instance iron carbonate (siderite), iron silicate (chamosite, glauconite, etc.), and iron sulphide (pyrite), are locally mined as iron ores.