Definition - What does Siderite mean?
Siderite is a type of mineral that is composed of iron (II) carbonate (FeCO3). Its name comes from the Greek term "sideros" which means iron. It is an essential iron mineral, as it is composed of 48% iron without phosphorus or sulfur.
This mineral is classified as calcite which is a cluster of carbonates that are all considered isomorphous. This mineral is characterized by an absolute rhombohedral cleavage.
Corrosionpedia explains Siderite
Siderite is a mineral that is characterized by a pearly or vitreous luster and white streak with a specific gravity equivalent to 3.96, and 3.75 to 4.25 Mohs hardness. Though it has useful applications, it can also be a product of corrosion. This is especially true in the case of carbon dioxide (CO2) corrosion.
Siderite is the major byproduct of corrosion that signifies corrosion caused by carbon dioxide. Most materials made from steel are prone to CO2 corrosion when CO2 partial pressure is higher than psi 7. This corrosion is distinguished by sharp edges, smooth bottoms, and sidewalls and pits that run into each other.
To form siderite, oxygen is required. However, this can be prevented by adding corrosion inhibitors directly into the system. Alloys that are corrosion resistant can also be added to fight corrosion.