Siderite Minerals
Siderite belongs to the group of calcite minerals, a group of related carbonates that are isomorphic to each other. They are similar in many physical properties and can partially or completely replace each other to form a series of solid solutions. All members of the calcite group crystallize in the trigonal system and have perfect rhombohedral cleavage
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Siderite Minerals
Siderite Description:
Siderite belongs to the group of calcite minerals, a group of related carbonates that are isomorphic to each other. They are similar in many physical properties and can partially or completely replace each other to form a series of solid solutions. All members of the calcite group crystallize in the trigonal system and have perfect rhombohedral cleavage.  Siderite is readily converted to iron oxide. Brown goethite substitutes for siderite are common. Limonite, an amorphous mineral, is commonly found in rhombohedral crystals as it is often pseudomorphic to rhomboid.  Stone siderite nodules are known to contain fossils of a variety of plants and animals, especially in open pit coal mines in eastern Illinois and western Indiana, and these stones are removed before the carbon veins are exposed. Commonly found in rocks
Siderite Associations:
Chemical Formula | FeCO3 |
Composition | Iron carbonate, usually containing some magnesium and calcium, sometimes also magnesium, zinc, and cobalt. |
Variable Formula | (Fe,Mg,Ca,Mn,Zn,Co)CO3 |
Color | Light to dark brown, yellow-brown, light yellow, yellow-green, greenish-brown, gray, and white. |
Streak | White |
Hardness | 3.5Â -Â 4 |
Crystal System | Hexagonal |
Siderite Color:
Siderite is carbonate of iron, and is of a light brown color, but can also be gray, yellow, yellowish brown, greenish brown and reddish brown because of impurities or the alteration to goethite.
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