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Ironstone is a fine-grained, heavy and compact sedimentary rock. Its main components are the carbonate or oxide of iron, clay and/or sand. It can be thought as a concretionary form of siderite. Ironstone also contains clay, and sometimes calcite and quartz.
[edit] AppearanceFreshly cleaved ironstone is usually grey. The brown external appearance is due to oxidation of its surface. Ironstone, being a sedimentary rock is not always homogeneous, and can be found in a red and black banded form called tiger iron, sometimes used for jewelry purposes. Sometimes ironstone hosts concretions or opal gems. [edit] OccurrenceIronstone mostly occurs in the form of nodules, for example in seams in the coal measures. [edit] Uses[edit] CeramicsIronstone is used as a component in some ceramics, commonly known as "ironstone china". Josiah Wedgwood manufactured a "stoneware" china in the 18th century. Charles James Mason perfected it as "Mason's Ironstone China" in the early 19th century. It was commonly used for heavy-duty dinner services in the 19th century.[1] Ironstone china was very popular during the 1970s. [edit] Ironstone as a source of ironIronstone is a bountiful and widespread source of iron (Fe), although it only contains less than 50 percent iron, far less than the other main source of iron, hematite. Historically, most of British iron originated from ironstone, but it is now rarely used for this purpose. [edit] See alsoPágina espejo de la WikipediaDirectorio de Enlaces Directorio dmoz Directorio espejo dmoz Pedro Bernardo |