ironstone

Ironstone is a term used to describe iron-rich rocks in geology and, less commonly, a type of durable ceramic tableware. In geology, ironstone denotes ferruginous sedimentary rocks that contain significant iron minerals such as hematite (Fe2O3), goethite (FeOOH), or siderite (FeCO3). These rocks can take the form of ferruginous sandstone, siltstone, or concretions and are often brown, red, or gray.

Formation and occurrence: Ironstone forms when iron-bearing minerals precipitate from iron-rich waters or during diagenetic replacement within sedimentary sequences. It may appear as hard, durable beds that weather slowly and can form nodules or layered bands. In some regions, ironstone beds have been economically important as sources of iron ore; historically mined examples include beds in Britain and North America.

Other uses: Beyond ore, ironstones have been used as decorative or building stones in various locales.

Ironstone china: In ceramics, ironstone refers to a durable white stoneware introduced in the early 19th century under the name ironstone china. It was marketed for strength and chip resistance and became widespread in Britain and the United States, with many factories producing ironstone tableware. Contemporary use retains the old name, though formulations vary.